Nick Kyrgios has fired another shot at Jannik Sinner to continue his war of words with the Wimbledon champion.
Sinner recently returned from a controversial three-month ban from tennis after testing positive for the banned anabolic steroid clostebol in two failed drug tests.
The Italian returned to reach the French Open final earlier this year and then defeated Carlos Alcaraz to win the men's Wimbledon singles title.
But Krygios believed Sinner's success after his doping violation was a negative look for the sport.
Now the dispute has resurfaced after the news broke that Sinner had re-appointed his former fitness coach Umberto Ferrara, who was fired over the doping case.
A statement from Sinner's team read: "Jannik Sinner has reappointed Umberto Ferrara as his fitness coach with immediate effect.
"The decision has been made in alignment with Jannik’s management team as part of ongoing preparations for upcoming tournaments, including the Cincinnati Open and U.S. Open.
“Umberto has played an important role in Jannik’s development to date, and his return reflects a renewed focus on continuity and performance at the highest level.”
Jannik Sinner. Image: Julian Finney / Staff via Getty Kyrgios reacted to the situation on X and wrote: "Unfortunately this isn’t @TennisCentel", referencing a parody tennis news account.
Why is Umberto Ferrara controversial?
Ferrara bought Trofodermin, which is an over-the-counter treatment available in Italy, although it contains the banned anabolic steroid clostebol. Sinner's physiotherapist, Giacomo Naldi, then used it on the Italian tennis star and the following month, the world No 1 recorded two positive tests for clostebol.
Authorities accepted that the substance had inadvertently entered his system through massages.
But the World Anti Doping Agency (WADA) appealed the verdict to the Court of Arbitration for Sport (CAS) and sought a two-year ban for Sinner.
In February 2025, Sinner reached a settlement with WADA and agreed upon an immediate three-month ban from tennis.
Jannik Sinner. Image: HENRY NICHOLLS / Contributor via Getty However, WADA did acknowledge that he did not intend to cheat and it did not provide a performance-enhancing benefit.
A statement released by Sinner's lawyers read: "This case had been hanging over me for nearly a year and the process still had a long time to run with a decision maybe only at the end of the year.
"I have always accepted that I am responsible for my team and realise Wada's strict rules are an important protection for the sport I love.
"On that basis I have accepted Wada's offer to resolve these proceedings on the basis of a three-month sanction."
Since returning to the court, Sinner has been outstanding, reaching the final of the French Open without dropping a set.
Although he was beaten at Rolland Garros in a five-set classic by Alcaraz, the Italian got his revenge at Wimbledon defeating the Spaniard in four sets.