Cahill, Vagnozzi break down the serve secrets behind Sinner’s Nitto ATP Finals win
Even in the midst of a standout 2025 on the ATP Tour, Jannik Sinner and his team knew that improvements were always possible.
The Italian crowned his season in style on Sunday night in Turin, where he overcame his great rival Carlos Alcaraz in straight sets to successfully defend his title at the Nitto ATP Finals. A key feature of Sinner’s trophy run at the prestigious season finale was his serve, and his coaches Darren Cahill and Simone Vagnozzi later reflected on the recent work they had done with that aspect of the World No. 2’s game.
“For sure after the US Open we saw some issues, especially with the serve,” said Vagnozzi at Inalpi Arena after Sinner’s 7-6(4), 7-5 final triumph. “We changed the motion. We changed the rhythm. He served really well from Shanghai until here. Today in the second set he struggled a little bit.
“I think Carlos changed his position on the second serve, changed something on the serve of Jannik also. The second set he started to serve too slow. This also changed the rhythm from the first set. On the serve, we changed a lot of things after the US Open. We are lucky to have Jannik, who is really fast to improve, to understand the changes and everything.”
Sinner had reached the championship match at all four majors in 2025 prior to the changes Vagnozzi spoke of, lifting the trophies at the Australian Open and Wimbledon, making it somewhat surprising that his coaches felt tweaks were even needed. But Cahill emphasised the need to work on what he called ‘the most important’ shot in tennis.
“You have control over one shot in tennis, and that is the serve,” said the Australian. “Jannik and Simone have done some incredible work over the last four or five weeks to rejig the serve and find that rhythm and tempo where he has been able to up the first-serve percentage.
“It is not just that about the first-serve percentage. If we were really concerned about the first-serve percentage, we would let him slow the serve down to let him get more first serves in. He’s actually pumped up the miles per hour, and he is getting the ball closer to the line, which means he gets a lot more free points. They’ve done a wonderful job with that.”
Time for a team photo with a special guest 🐶😅 @janniksin | #NittoATPFinals pic.twitter.com/NAoSRQ5xFA
— ATP Tour (@atptour) November 16, 2025
The results since certainly prove Cahill’s theory. After his final defeat to Alcaraz in New York, Sinner lifted ATP 500 titles in Beijing and Vienna, an ATP Masters 1000 crown in Paris, and the Nitto ATP Finals trophy. The 24-year-old has finished his season with a 58-6 record, according to the Infosys ATP Win/Loss Index.
Sinner’s Turin victory against Alcaraz, in which he saved a set point in the first set and rallied from 1-3 to clinch the second, reduced his Lexus ATP Head2Head deficit against the Spaniard to 6-10. Vagnozzi was delighted with the way his charge had held his nerve in front of thousands of adoring home fans.
“It was a really emotional match. Really tight match,” said the coach. “I think both of them, they had periods when they played really good, and sometimes they made some mistakes. We saw Jannik always fighting with a good attitude, with a good face. He always believed, also in the second set when he was a break down, couldn’t change the direction of the set.
“We are really happy about Jannik’s performance. I think there is still something to work on also after this win, the match showed something that we can try to make better. But I’m really happy how we finished the season with unbelievable three tournaments in a row. We are pumped to start next season.”
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