Having won 20 grand slam titles during a glittering career, one might think that Roger Federer has seen it all.
Yet the 37-year-old Swiss admits he is stepping into the unknown as he returns to the French Open after a three-year hiatus.
The former world number one won his only Roland Garros title back in 2009, and he wanted to give it another go after skipping the last three editions of the claycourt major.
Asked if he thought he could lift the Musketeers` Cup on June 9, Federer replied: "I don`t know. A bit of a question mark for me. Some ways I feel similar to maybe the Australian Open in 2017. A bit of the unknown," Federer told reporters on Friday referring to his comeback to the season`s first major in 2017 after being out of action for six months.
"I feel like I`m playing good tennis but ... is it enough against the absolute top guys when it really comes to the crunch? I`m not sure if it`s in my racket."
"But I hope I can get myself in that position deep down in the tournament against the top guys. But first I need to get there and I know that`s a challenge in itself. Yeah, it`s definitely going to be an exciting tournament mentally to go through."
Federer will kick off his campaign against Italian Lorenzo Sonego and has a relatively easy path until the quarter-finals, where he could meet Greek Stefanos Tsitsipas before a potential semi-final against 11-time champion Rafael Nadal, whom he has never beaten at the French Open.
Federer won the title in 2009 after Nadal had been beaten by Swede Robin Soderling midway through the event. Federer then defeated Soderling in the final to complete his career slam.
Looking back to that tournament 10 years ago, Federer said he was happy he managed to handle the pressure as expectations could have crushed him following Nadal`s exit.
"This is where these expectations started when the journalists started saying it`s this year or never," he explained.
"From then on, the next nine or 10 days felt like forever. (When) Soderling had beaten Rafa... I knew that instead of the tournament becoming easier, it was going to become more difficult because of the pressure," added the Swiss, who was stretched to five sets in his fourth round and semi-final matches after news of Nadal`s demise had already hit the headlines.
"But it was nevertheless interesting and I felt better, and I feel proud that I was able to manage the pressure."