Roger Federer started his French Open campaign last week with no expectations.
He was playing well, reaching the quarter-finals at his two warm-up tournaments in Madrid and Rome. But he hadn't played on clay since a straight-sets quarter-final defeat at Roland Garros by Stan Wawrinka in 2015. His compatriot would go on to win the title.
Tonight the good friends meet again, from hoping he would play well enough to get into the second week, Federer must surely now believe he is a genuine threat for the title.
He's hitting the ball as well as he ever has on clay, a surface he grew up on and from between 2005 and 2012 was the best player in the world on the surface, after Rafael Nadal.
While the 20-time Grand Slam champion has won this title just once, in 2009, he reached the semifinals in 2005 and 2012 and was runner up to Nadal in 2006, 2007, 2008 and 2011.
Back then there was more pressure on Federer, now at nearly 38 he may well be playing here for the final time. He is unlikely to play Roland Garros in 2020 when the tennis calendar is more congested due to the Tokyo Olympics, where it's thought, at the age of 39, he could finally call the end to a remarkable career.
In Paris, Federer is playing with no fear of failure, with freedom to showcase his full repertoire.
Federer knows he can't get drawn into lengthy rallies against real clay-court grinders. So far he's relied on variety, mixing in sliced backhands with top-spin attacking returns, drop shots and precise serve and volleying.
Sure, he has beaten two players ranked outside the top 100 and 68th-ranked Leonardo Mayer. Wawrinka will be a massive step up and the 24th seed has been producing the sort of tennis that took him to the title here four years ago. But he's had a much tougher path to the quarter-finals, winning three tie breakers against Grigor Dimitrov in the third round before playing the match of the tournament yesterday against Stefanos Tsitsipas.
He has had less than 48 hours to recover from that five-hour nine-minute five-set epic victory over the Greek 19-year-old in what was a match of extraordinary quality.
By comparison, Federer has barely raised a sweat and will be by far the fresher of the two. Federer owns their head-to-head record at 22-3 and has won all six of their meetings since that straight-sets defeat here in 2015. And while those wins have come on hard courts, Federer starts as favourite.
Suddenly a dream "FEDAL" semifinal becomes a possibility as Rafael Nadal will be sure to take care of a fatigued Kei Nishikori in the other semi.
In all those finals against Nadal I never really gave Federer a chance. Back then the Spaniard successfully peppered the Federer backhand, generating so much spin and bounce that he had Federer trying to slice the return from above his shoulders.
But Federer has changed his game since then ... in 2017 when he beat Nadal in an epic Australian Open final he employed an attacking top-spin back-hand return with great success, and gave Rafa less time to dictate with his punishing forehand.
Federer hasn't lost to Nadal since 2014 and has won their past five matches. While the King of Clay, who has lost just twice in 92 matches at Roland Garros, will still be favourite, I think Federer stands a genuine chance of winning should the great rivals meet in the semis.
It's truly incredible to think that about a player who made his Grand Slam debut at Roland Garros in 1999, 20 years ago.
Matt Brown is in Paris courtesy of Emirates Airline