PARIS — There were plenty of recent reasons for Stefanos Tsitsipas to doubt himself, to wonder how things could keep going so awry.
And yet here he is, a French Open semifinalist for the first time.
The fifth-seeded Tsitsipas completely changed the match’s complexion Wednesday with a little help from his opponent, 13th-seeded Andrey Rublev, using a run of five consecutive games, and 11 of 13, to take control on the way to a 7-5, 6-2, 6-3 victory in the quarterfinals at Roland Garros.
Tsitsipas trailed by a break early but got that back when Rublev made four unforced errors while serving for the first set. And Tsitsipas was on his way, accumulating more than twice as many winners, 35, as unforced errors, 17, and taking the point on 16 of his 17 trips to the net.
After serving out the win at love, ending it with a volley winner, Tsitsipas stood at the net with a wide smile.
To think: At the last Grand Slam tournament, the US Open, Tsitsipas failed to convert a half-dozen match points and allowed a massive lead — two sets to one, 5-1 in the fourth — to disappear against Borna Coric in the third round last month.
Then, against Rublev in the final of the clay-court Hamburg Open on Sept. 27, which also was Day 1 of the French Open, Tsitsipas served for the victory at 5-4 in the third set and again could not close it out, absorbing another disheartening loss.
And then, two days after that, in Paris, Tsitsipas ceded the initial two sets of his first-round match against 109th-ranked Jaume Munar.
Tsitsipas did not let that deficit daunt him. Nor, clearly, was he too burdened by his recent foibles, because not only did he take the next three sets that day to beat Munar, but Tsitsipas has not lost a single set since.
“I know the past few weeks have been a little bit difficult with certain losses that I had, and a bit unusual, to be honest,” Tsitsipas said after that first-round win, “but I’m trying to learn from them, grow from them, and trying to put them behind and continue stronger.”
On Friday, Tsitsipas will face No. 1 Novak Djokovic or No. 17 seed Pablo Carreno Busta. Their quarterfinal — a rematch of the US Open match in which Djokovic was disqualified — was scheduled for later Wednesday.
The other semifinal Friday is No. 2 Rafael Nadal vs. No. 12 Diego Schwartzman.
Nadal is seeking a record-extending 13th championship at Roland Garros, which would raise his Grand Slam trophy total to 20, equaling Roger Federer‘s record for men. Schwartzman never has played in a major semifinal.