Jannik Sinner’s 117 mph Second Serve That Flipped the 2025 ATP Finals

The serve that changed Turin

Scoreboard says danger. First set, 5–6, 40/Ad in the Nitto ATP Finals title match. Carlos Alcaraz leans forward on the baseline. Jannik Sinner bounces the ball, looks up, and does the one thing most juniors are taught not to do on a second serve at set point. He hits it harder. A 117 mph body serve that jams Alcaraz and erases the set point. Sinner holds, wins the tiebreak, then the match. The official match report even calls out the play by speed and moment, crediting the “117 mph second serve on set point.” That is the template for a green-light second serve under pressure. 117 mph second serve on set point.

This was not a heat-of-the-moment gamble. It was preparation meeting a clear decision rule. Sinner had the scouting, the routine, and the nerve to choose a high-upside option right when the set and momentum hung in the balance.

This article breaks down why a go-big second serve can be the right play, how to decide when to do it, what to look for in opponent patterns, and the exact practice structure that builds clutch execution. We will anchor everything to Sinner’s set-point save, his undefeated title run in Turin, and the way he closed 2025 on a historic indoor streak documented by multiple outlets as 31 straight wins. See the recap that notes his “31 straight indoor wins.” 31 straight indoor wins. For deeper context on his pressure habits, see our piece on pressure routines and first-strike patterns, and for the other side of the net, study Alcaraz’s Turin pressure blueprint.

What a green-light second serve really means

A green-light second serve is not reckless. It is a planned, higher-pace or higher-intent second serve chosen when the expected value is better than your default spin serve. The idea is simple:

• Your default second serve gives the returner a comfortable swing. Against elite returners, that is almost a neutralization or worse.
• A faster, better-placed second serve to a precision target can remove the returner’s preferred contact point and reduce their swing length. The body serve is the classic example because it compresses space and forces a late decision.
• Indoors, with no wind and predictable bounce, the error bars shrink. If you can hit your spot, your upside rises.

Sinner’s 117 mph body serve checks every box. He chose speed plus location to remove Alcaraz’s forehand backswing, betting that jam-contact at that speed would produce a block or miss rather than a full-blooded rip.

The risk math in plain English

Think of serve choices like an investment with risk bands. Here is a simple expected-value picture any player or coach can use.

• Baseline option: Roll a safe kick second serve to the backhand. Against a returner like Alcaraz, the reply comes back deep 7 out of 10 times, and 2 out of 10 times it is immediately offensive. You start neutral or slightly defensive.
• Green-light option: Hit a faster second serve into the body on the ad side. You will miss a few more serves, but when you land it, the return quality drops, and many replies float middle or sit up. Your plus-one forehand becomes available.

Expected value improves if three things are true: your location accuracy is strong, your opponent’s backswing needs space, and the court rewards first-strike tennis. In Turin those conditions were met. Sinner had been landing his spots all week, Alcaraz likes taking a full cut on second-serve returns, and indoor hard at the Inalpi Arena rewarded clean contact. For match-to-match planning, also see Sinner’s indoor blueprint for Turin.

The Green-Light Index: a quick decision tool

Use this five-question checklist at the back fence while you dry the ball. Score 0, 1, or 2 on each. A 6 or higher is a green light.

1. Point leverage. How much does winning this point swing the set? Break points, set points, and 30-all on serve are high leverage. Score 2 for those.
2. Accuracy feel today. Are you locating your second serve targets at least 7 out of 10 in warmup and early games? If yes, score 2.
3. Returner discomfort. Does the opponent hate the body serve or the wide kicker? Have you drawn two or more shanks or jammed blocks already? If yes, score 2.
4. Surface and ball. Indoors or still conditions add control. Faster, lower-bouncing surfaces help jam serves. If conditions favor precision, score 2.
5. Plus-one readiness. Do you know the next ball pattern and have a simple first move? If yes, score 2.

Sinner’s moment likely graded 2, 2, 2, 2, 2. Full green.

Serve-pattern scouting you can borrow from Sinner

• Body on the ad side vs forehand-based returners. Many right-handers on the ad side want to step in and drive forehand up the line or inside-out. A body serve into their hip removes extension, often producing a short block middle. Sinner went hard to the torso and froze Alcaraz’s feet.
• Two-way miss insurance. The body target offers bigger margins than the lines. If you pull it slightly, the ball leaks to backhand hip. If you push it, it leaks to forehand hip. Either way, you still invade space instead of feeding a full swing.
• Jam then run. If you jam to the body, plan the plus-one to the weaker corner you have already mapped. Sinner’s plan after jamming Alcaraz is often forehand to the backhand corner, then a forehand inside-in if the reply lands short.
• Hide the toss, not the intent. Big moments invite readable tosses. Keep toss height and location consistent. Your disguise should be racquet speed and the late wrist pronation, not a last-second toss change that ruins timing.

The pre-serve routine that buys you courage

Here is a compact routine you can apply tomorrow. It lasts about 12 seconds and resets your nervous system without theatrics.

1. Breathe 1:2. Inhale for a silent count of 3 through the nose. Exhale for 6 through the mouth. Long exhale tells your body this is fine. Two cycles are plenty.
2. Narrow focus. Eyes on the back of the ball as you bounce it. Then lift eyes to your target and attach one simple verb to it. Example cue: “Jam.”
3. Commit out loud. Whisper your plan so only you hear it. “Body ad, forehand first ball.”
4. Physical trigger. Squeeze the racquet handle for one second while exhaling. This is your go signal.
5. Immediate plus-one move. Before you toss, arrange your first step after contact. If jammed return floats, cheat one step to your forehand.

The routine is a contract. Once you toss, the decision is closed. No mid-air edits.

How to build 117 mph under the hood

You do not need 117 mph to win big points. You need the fastest version of your dependable second serve with a precise target. Here are technical cues that scale to every level.

• Toss slightly into the court. That lets your hips drive through so contact is forward, not on your ear. Forward contact makes the body target hit with depth rather than sitting up.
• More spin, not less. Speed does not mean flat. Think 70 percent slice, 30 percent topspin for the ad-side body serve. The sidespin pulls into the torso; the topspin drags it down into the box.
• Lead with the edge. Feel the racquet edge slicing air on the way up. That preserves racquet-head speed and sets up late pronation.
• Jump to your landing spot. Land inside the court on your left leg if you serve right-handed. That puts you in position for the plus-one forehand.
• Aim small. Use a two-ball-sized window on the ad service box T-meets-body seam. Place a cone there in practice.

Equipment note. A stiffer frame will return energy, but only if your contact is out front. Sinner swings a Head frame, Alcaraz a Babolat, yet both optimize by timing and pronation, not just gear. Tech helps, technique wins.

Drills that build clutch second serves

Use these with a coach, a practice partner, or solo with a basket. If you have a radar or a court camera, great. If not, no problem. Use targets and outcome tracking.

1. Body-line ladder

• Place three disc targets along the ad-side body seam: near T, mid seam, and deep seam.
• Hit 10 second serves to each, score 1 for any within two racquet lengths of the disc. Goal is 20 out of 30 before you raise pace.

2. Jam and run plus-one

• Serve a body second serve, then coach hand-feeds a block return to the center. You must hit a forehand deep cross, then a forehand inside-in to finish. Score one only if the serve lands near target and both groundstrokes clear the service line.

3. Pressure countdown

• You start at 10. Each double fault is minus 2. Each made serve to the target is plus 1. Must end at 15. If not, repeat the set.

4. Tiebreak builder

• Play a 7-point breaker where every point begins with a second serve to a called target. If you miss long or wide by more than two racquet lengths, you lose two points. This punishes reckless speed without shape.

5. Green-light scrimmage

• Practice sets where every 30-all, game point, or break point requires a go-big second serve. Use the Green-Light Index. Track results in a small notebook.

6. Breath plus commitment reps

• Two breath cycles, whisper the plan, serve within three seconds. If you bounce longer than three seconds after the second exhale, the rep does not count. This trains decision closure.

Calibrating risk like a pro

Players and parents often ask, how many double faults are OK if I am serving bigger? The rule of thumb for a green-light strategy is simple: your double faults can rise slightly if your free points and weak returns rise more. Track three metrics across a month of practice and matches.

• Targeted second-serve make percentage. Aim for 65 to 75 percent on your body second serves at match pace.
• Weak return rate forced. Count any returns that land short middle or pop up. A good goal is 40 percent on green-light attempts.
• Plus-one conversion. If you get a weak reply, do you win the point within two shots 60 percent of the time? If not, the serve is working but the plus-one plan needs attention.

If those numbers are trending positive, a small increase in double faults is not only acceptable but productive.

Case study: why Sinner’s choice worked

• Pattern history. Alcaraz is an elite returner, but his most explosive second-serve return is a full swing. The body serve denies that swing. Sinner had already established body serves during the week, and the jammed contact had produced blocks.
• Indoors and rhythm. Indoor conditions remove wind variables and exaggerate clean timing. That favors the server who commits.
• Scoreboard effect. Saving that set point did more than keep the set alive. It signaled to Alcaraz that Sinner would not blink on seconds. That threat alters return positioning in future games.
• Plus-one clarity. Sinner’s first step after contact was forward and slightly right. He was set to take a middle reply with his forehand. Commitment shows up as footwork, not just courage.

The lesson is not that everyone should hit 117 mph. The lesson is that when your scouting, routine, and math align, going bigger is the safer option because it removes your opponent’s weapon.

Coaching the green-light serve at the academy level

• Build the routine into every basket session. Do not separate mental work from technical reps. Two breath cycles and a whispered plan before every second-serve ball.
• Scout opponents in clusters. Create simple tags like “backswing hungry,” “chipper,” or “early stepper.” Body serves beat backswing hungry players. High kick to the backhand beats chippers. Quick wide slice punishes early steppers.
• Video the hips and contact, not just the arm. Most second-serve misses under pressure come from a toss that drifts back or hips that stall. Use a back-view camera on the baseline.
• Use constraint scoring. Only count a serve rep if you land in the target window and finish the point with the intended pattern.

What juniors can copy on Monday

• Pick one green-light target. For two weeks, choose ad-side body as your only green-light target. Simpler is faster under stress.
• Install the 12-second routine. Write it on a card in your bag. Inhale 3, exhale 6, repeat. Cue word. Whisper plan. Squeeze. Toss.
• Run the Pressure countdown drill three times a week. Track your score. When you end at 15 two sessions in a row, raise the target speed or shrink the target cone.
• Measure outcomes, not myths. If you cannot afford a radar, count weak returns forced. That is the payoff you actually want.
• Add OffCourt to your toolkit. Off-court training is the most underused lever in tennis. OffCourt unlocks it with personalized physical and mental programs built from how you actually play. Use it to build breathing habits, commitment cues, and serve-specific strength that translates to the court.

Mistakes to avoid

• Aiming near lines at big moments. Go body or big window out wide. Lines invite hero ball misses.
• Slowing down the arm on second serves. Keep racquet speed constant and adjust shape with spin.
• Changing the toss late. Disguise with racquet speed and pronation, not a new toss location.
• Fuzzy plus-one plans. If you do not know your first step after contact, you are not green-lighting, you are guessing.

Final word

Sinner’s 117 mph second serve at set point was not a dare. It was a high percentage answer to a high leverage question, made possible by clear scouting, a clean routine, and reps that baked courage into muscle memory. If you are a junior, a coach, or a parent, the blueprint is on the tape and in your next practice. Install a routine that closes the decision before the toss. Train a single green-light target until it is automatic. Track outcomes that matter. And when the biggest points arrive, choose the serve that takes your opponent’s swing away.

Turin reminded everyone that bravery can be engineered. Start building yours today. Then bring your plan to your next match and give yourself the green light.