Stefanos Tsitsipas was again made to work hard for victory, the Greek fourth seed overcoming Czech qualifier Zdenek Kolar 6-3 7-6(8) 6-7(3) 7-6(7) in a marathon match on Thursday to move into the French Open third round.

Two days after the 23-year-old Tsitsipas came from two sets down to beat Italian Lorenzo Musetti at the claycourt Grand Slam, there was another nail-biter for the 2021 finalist.

The match appeared headed for a deciding set when Tsitsipas found himself down four set points in the tiebreaker but the Greek found a way to save them all before converting his second match point after four hours and six minutes.

Tsitsipas slammed his racket down in frustration after forcing an error from Kolar as the crowd erupted in appreciation.

“He drove me crazy. It was really frustrating,” Tsitsipas said in his on-court interview.

“He was putting every part of his body behind the ball. I’d like to congratulate him for this effort.”

Kolar made his main draw debut at Roland Garros this year after losing in the qualifiers the last four times and pulled off his first tour-level victory over Frenchman Lucas Pouille in the opening round.

In his first clash with Kolar, Tsitsipas made a strong start on Court Suzanne Lenglen to bag the opening set in 35 minutes but he was soon forced to play catchup with the 134th-ranked Czech racing to a 4-1 lead in the second.

But the Greek, who won the first two sets of the 2021 French Open final before going down to world number one Novak Djokovic, went up a gear to level before taking the second set after a long tiebreaker.

The 25-year-old Kolar showed big heart and with vocal support from the crowd supporting the underdog, he stayed in touch with Tsitsipas in the third set and dominated the tiebreaker to force a fourth.

After trading service breaks through the set, Kolar was a point away from forcing a fifth but was unable to convert his chances in the tiebreaker.

Tsitsipas will meet 95th-ranked Mikael Ymer of Sweden for a place in the fourth round.