Darren Cahill says the work he and Simone Vagnozzi have done with Jannik Sinner focused on adding avenues to finish points, and that those changes helped convert a top-10 talent into a sustained world No 1. Cahill, who previously mentored Lleyton Hewitt and Andre Agassi, joined Sinner in July 2022, shortly after Vagnozzi began with the then rising player.

Under the two coaches Sinner has claimed two Australian Open titles, one US Open crown and the 2025 Wimbledon trophy. The 23-year-old has also spent the last 62 weeks at the top of the ATP Rankings and has been unmovable since becoming the first Italian world No 1 in June 2024.

On the coaching partnership Cahill was specific about roles and process. “I work hand-in-hand with Simone, he started about six months before I did, and he has been amazing. He had a vision for where Jannik’s game needed to go and we spent a lot of time together working through what technical changes he had to make,” he revealed.

Cahill described the technical priorities in detail. “Anything from a technical point of view, creating more ways for him to develop finishing skills, with his serve a little bit, his transition skills, all the stuff that all the great champions of the sport have in their arsenal.

“Jannik was already a great player, he was already a top-10 player, he hit the ball great from the back of the court, but he needed to work on more avenues to finish points.

“And so we went to work and we a really fortunate that we have a player who wants to get better every single day, he never settles for where he is at the moment, no matter what he achieves and every time he steps onto the court he is looking to improve as a tennis player.”

Cahill singled out the serve as a turning point. “One thing I did say is, ‘The serve needs to improve. You’re six foot four and you’re a strong lad’,” he revealed. “‘You need to be able to get more miles per hour on that first serve, better direction on that first serve.

“Then not only do you start winning some free points from your first serve, but also your Plus One becomes much more effective. If people can neutralise your serve, you have to work much harder for your points.

“Then his questions came, one after the other ‘How do I get better at the serve? What do I need to do?’ It’s typical of him. He wants to compete. He’s a competition animal.”

On the current landscape Cahill noted the separation at the top. “We’re seeing an incredible level of tennis at the moment, with Carlos and Jannik.

“If you look at their body of work over the past couple of years, they’ve separated themselves from the field. Now it’s up to the field to chase, to watch and copycat a little bit, to work a little bit harder and to work on the things they are working on, do what everyone does and that’s try to be as good as the best.

“We are very fortunate as coaches and it has been a wonderful journey so far.”

Carlos Alcaraz moved to 50 match wins for the year with a straight-sets victory at the Cincinnati Open, defeating Hamad Medjedovic 6-4, 6-4 on Tuesday. The 22-year-old had been pushed to three sets two days earlier, but produced a cleaner performance against his fellow 22-year-old to register the milestone.

Alcaraz is the first player, male or female, to reach 50 wins in 2025. On the men’s tour Alexander Zverev has the next-most wins with 40, while on the women’s side Aryna Sabalenka leads with 49. Jessica Pegula can move closer to that group: she would notch her 38th victory of the year if she wins her third-round match against Magda Linette tonight.

The win in Cincinnati also continued two longer-running threads. With his victory over Medjedovic, Alcaraz remains unbeaten against players younger than him; he is now 10-0 versus younger opponents. More broadly, Alcaraz is the only man to record 50 or more match wins in each of the last four seasons. No other male player can join him in that distinction, because he was the only man to reach 50 wins in 2022, 2023 and 2024.

There is one woman who can match that four-year consistency: Iga Swiatek. Swiatek won 67 matches in 2022, 68 matches in 2023 and 64 matches in 2024, the only woman with those three totals in that span.

Alcaraz’s Cincinnati victory is therefore both a stand-alone milestone and another entry in a sustained run of high-volume winning. The 50th win underscores his place at the top of the season-long charts and highlights how few players, male or female, have combined volume and consistency across multiple seasons.

© 2025 Daniel Kopatsch

Jannik Sinner enters the North American hard-court swing carrying a 23-match unbeaten run on the surface, a sequence that stretches back nearly a year to the 2024 China Open final. His last loss on hard courts came in that final, when Carlos Alcaraz beat him 6-7 (6-8), 6-4, 7-6 (7-3).

The current run began at the Shanghai Masters in October, where Sinner won six matches in a row, including the final against Djokovic. He followed that with an ATP Finals title run, winning five consecutive matches and defeating Taylor Fritz in the final, which took his unbeaten tally to 11. Sinner then closed the 2024 season with three wins at the Davis Cup finals as he helped Italy defend the title, moving the streak to 14. He extended it at the Australian Open with seven wins during his title run on the hard courts of Melbourne Park to reach 21.

Sinner was then banned from February until the start of May due to his two failed doping tests in March 2024 and missed the hard-court Sunshine Double at Indian Wells and Miami. Returning to competition after the clay and grass seasons, he won at Cincinnati, beating Daniel Elahi Galan and then Gabriel Diallo 6-2, 7-6 (8-6) to bring the streak to 23.

Comparisons with the era’s best make clear the scale of the challenge ahead. Roger Federer’s longest hard-court run reached 56 matches, a sequence that began at the 2005 Rotterdam Open and ended at the 2006 Dubai Tennis Championships. Federer also recorded streaks of 36 and 26 on hard courts. Novak Djokovic’s longest hard-court run stretched from December 2010 until August 2011; that period included titles at the Australian Open, Dubai, Indian Wells, Miami and Canada before he lost the Cincinnati Open final to Andy Murray. Djokovic also has hard-court runs of 29, 26 and 23.

Rafael Nadal enjoyed an extended hard-court run from March 2012 until October 2013 with wins at the 2012 Miami Open, Indian Wells, Canada, Cincinnati and the US Open, before losing the China Open final to Djokovic. Murray’s streaks are also noted in recent seasons, with a run in early 2017 ended by Djokovic in the Doha final.

Sinner’s 23-match streak is substantial, but historically it still sits below the benchmark set by Federer and some of Djokovic’s longest runs.