Jakub Mensik broke through in 2024, when he competed in the Next Gen ATP Finals presented by PIF. But an Infosys ATP Beyond The Numbers analysis shows that he has taken his game to new heights in 2025 behind an improved first serve.
First-serve percentage is always important, but not usually the key factor in determining wins and losses. Carlos Alcaraz is 18th in first-serve percentage this season at 65 per cent, according to Infosys ATP Stats. Mensik is 35th at 60.5 per cent.
But this year has shown just how important the shot is to his game. The 19-year-old played an ATP Challenger Tour event in March in Cap Cana, losing a three-setter in the semi-finals to Damir Dzumhur, against whom he landed only 47 per cent of his first serves. The following week at the Miami Open presented by Itau, Mensik made at least 65 per cent of his first serves in all six of his matches.
The teen departed the ATP Masters 1000 event with his first ATP Tour title.
Mensik's First-Serve Performance In Miami
| Match | First-Serve % | First-Serve Pts Won |
| F vs. Djokovic | 66.7% | 76.9% |
| SF vs. Fritz | 72.3% | 82.2% |
| QF vs. Fils | 66% | 85.7% |
| R32 vs. Safiullin | 74.5% | 87.8% |
| R64 vs. Draper | 65.8% | 86% |
| R128 vs. Bautista Agut | 66.3% | 84.2% |
| Total | 68.6% | 83.4% |
According to his head coach, Tomas Josefus, his first-serve improvement was the key to his breakthrough in Miami.
“I told Jakub in the past, many times, you don't have to be good in everything, but you have to be good in something,” Josefus said. “Jakub, he basically played completely same performance, for example, as in during a Challenger in the Dominican Republic, but his serve was much better. He improved his first-serve percentage, especially.
“His first-serve efficiency went higher and of course, conditions, it was a big help for Jakub, because the surface and the court pace index was definitely much higher than during the tournament in Indian Wells. So basically, the only one reason was serve performance.”
It is not just that Mensik made his first serves, but what it led to. In Miami, he won a significantly higher rate of first-serve points (83%) than he has on average in 2025 (79%) and throughout his career (76%).
"The serve is the only stroke in your game that you have time for. You can basically do whatever you want and try to really focus beforehand,” Mensik told ATPTour.com in Munich. “The preparation before, you can take time and think about it. When you play forehands or backhands, you don't have time at all, so of course it's really important how you start a point.
“For me, of course, with my height and everything, it's a very big weapon. From a young age, the serve was one of my favourite strokes in the game.”
In Miami, Mensik enjoyed some of his best serving days for the season. Five of the six tour-level matches in which he made the highest rate of first serves this year came at the Masters 1000 event, as did four of his five best days in first-serve points won percentage. Josefus, who said that Mensik has been working with a mental coach, believes a lot of the positive results stemmed from his pre-serve preparation.
“He didn't rush, because sometimes when he is under pressure, when he feels some pressure from personal life and this type of stuff as well, he has very often tendencies and during matches as well, rushing between the points,” Josefus said. “So basically, the break between the end of his previous point and then first serve, it's only eight, then maximum 12 seconds. But in Miami, he wasn't rushing.”
The result was winning 93 per cent of his service games and lifting the trophy at the end of the tournament.
Mensik's Serving Statistics
| Stat | Miami | 2025 | Career |
| First-Serve Percentage | 69% | 61% | 59% |
| First-Serve Points Won | 83% | 79% | 76% |
| Second-Serve Points Won | 48% | 48% | 48% |
| Service Games Won | 93% | 86% | 82% |
Was it just key in Miami?
This was not a one-tournament story for Mensik and his first serve. There has been a theme for the teen: land his first delivery and win matches.
In 2025, Mensik has averaged a 63 per cent first-serve rate in matches he has won versus 54 per cent in matches he has lost. His Top 10 serving days in terms of first serves made have all resulted in victories.
For many players, landing more first serves requires dialing back the speed and aiming for safer targets, which makes it easier for the returner.
But Mensik is showing that when his serve is on, he is not only making a lot of them, but devastating his opponents. Former World No. 1 Andy Roddick has taken notice, discussing it on his Served with Andy Roddick podcast following Miami.
"My biggest takeaway is that serve is going to win him a lot of matches when he’s not playing perfectly in other parts of his game," Roddick said. "His first serve is elite, his ability to hit all four corners off the same toss."
Mensik's first serve — his magic maker — is the biggest reason why he is ninth in the PIF ATP Live Race To Turin and in early contention for the Nitto ATP Finals.
"In past years and last year, sometimes I didn't feel that much consistency in my serve, but it's just a part of the game that I got some experience in,” Mensik said. “I practised a bit, played a lot of matches, and I can say the consistency in my serve is much better these days.”
- Jon Jeraj contributed research for this story.
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