Former US Open champion Marin Cilic has claimed there are “not answered” questions following the resolution of Jannik Sinner’s doping case.

World No 1 and three-time Grand Slam champion Sinner has been banned for three months after twice testing positive for clostebol back in March 2024.

The 23-year-old  settled with the World Anti-Doping Agency (WADA) earlier this month, having initially been found to be of “no fault” – and handed no suspension – by the International Tennis Integrity Agency (ITIA).

WADA announced its appeal into the ITIA’s ruling last September, though the settlement with Sinner means that the case will no longer be heard by the Court of Arbitration for Sport (CAS) in April.

Had WADA been successful in an appeal to CAS, 23-year-old Sinner could have faced a ban of up to two years in length.

While a three-month suspension may ultimately be seen as a positive outcome for the Italian, the unexpected announcement of a settlement has taken many by surprise.

Among those left surprised was former world No 3 Cilic, who knows better than most the complexities behind doping cases.

The Croatian tested positive for banned substance nikethamide in April 2013 and was initially handed a nine-month suspension, though this was later reduced to four months on appeal.

Speaking at the Dubai Tennis Championships this week, the 36-year-old revealed he did not know it was “possible” to approach a settlement with WADA.

While he also defended Sinner, Cilic expressed his belief that there were still “not answered” issues surrounding the process faced by the Italian.

He said: “I didn’t know that was possible.

“Looking at it as a player-to-player, I am happy for Jannik that finally he’s going to be out of it. He’s going to have his mind free. I completely believe him in his story.

“I know him for many years. When he was a kid, you could see he’s like a true athlete. [I am] Happy that he can go through, but it raises questions, many questions which are not answered yet.”

Cilic’s Dubai campaign ended with a quarter-final defeat to Felix Auger-Aliassime on Thursday, though his run will still see him jump back into the top 150 of the ATP Rankings on Monday.

Meanwhile, Sinner will not be back in ATP action until the Italian Open in Rome, which starts just days after his suspension period ends on May 4th.

The world No 1 will not be able to defend his Miami Open title and will also miss out on playing further Masters 1000 events in Indian Wells, Monte Carlo, and Madrid.

However, he will return in time for his home event, before playing at Roland Garros later in May.