Darren Cahill, the Australian tennis supercoach, can celebrate the remarkable achievement of guiding a fourth player to become a world No.1, as his brilliant young charge Jannik Sinner ascended to the top of the global men's game.
The 22-year-old Italian learned he had become Italy's first world No.1 player, man or woman, on Tuesday after the current main man Novak Djokovic was forced to pull out of the French Open with injury.
When the new rankings come out on Monday, Sinner will join Lleyton Hewitt, Andre Agassi and Simona Halep as players that Cahill, the 58-year-old former player from Adelaide with the magic coaching touch, has led to the very top of the game.
His mentoring brought a warm tribute from Sinner, who has blossomed into an Australian Open champion and a Davis Cup-winning spearhead in the two years since Cahill joined his team as his co-coach alongside Italian Simone Vagnozzi.
"We started to work together nearly two years now. It's obviously a huge pleasure for me to have him," said Sinner, .
"I still remember the first week we had in Eastbourne on grass. Immediately I had good feelings with him because he has a lot of experience, and I knew that he brought different kind of players to world number one.
"He had great achievements also with different players. He knows how to adapt to each player, and I think this is a quality that's amazing.
"Also the combination with Simone is really, really good. They're two different coaches, but they work together really well. They are very humble, and they respect each other very much.
"I think the combination is very good. I'm lucky to have both of them and all the rest of the team."
After retiring as a player, Cahill guided fellow Australian Hewitt to become, at the time, the youngest player to become world No.1, before then helping Andre Agassi become the oldest in May 2003.
In 2017 and 2018, he coached Romanian Halep to the WTA top spot as well as guiding her to the French Open title. He's also had success as a consultant with high-profile players like Andy Murray, Ana Ivanovic, Fernando Verdasco and Daniela Hantuchova.
After Sinner had gone to No.2 in April after winning the Miami Open, Cahill noted that his charge was only going to improve.
"He can get better," said Cahill. "You evolve, you get a little bit older, a bit stronger, a bit faster, a bit smarter, all those things are going to start coming into his game."
Sinner has now become the second player born in the 2000s to reach the top, along with Carlos Alcaraz.
"I think it's great for Italy, we're a great country with great coaches and players and we can see now how this moment is," Sinner said of the new wave of Italian talent. This includes six players in the men's top-53 and the world's No.15 women's player Jasmine Paolini.
"I'm happy to be part of this Italian movement. People, they start to play tennis now more and more, which is great to see. I think that's the most important."
