One of the favourites to lift the French Open Trophy, Stefanos Tsitsipas had a tough time seeing off Czech player Zdenek Kolar 6-3, 7-6(8,) (3)6-7, 7-6(7) in their second-round encounter on Friday (AEST).

“He drove me crazy,” Tsitsipas said after the game that lasted four hours and six minutes. “It was so frustrating, he was just behind every ball and it was not easy.”

“Mr Kolar was putting every part of his body behind the ball and I would like to congratulate him on such an incredible effort,” the Greek world number 4 told eurosport.com.

Kolar, 25, who is ranked 114 in the world, played from the back of the court and varied his shots with a mix of lobs, drop shots and slices to keep Tsitsipas on high alert throughout the match. However, the Greek’s superior power and experience eventually gave him the victory.

Tsitsipas took the first set after an early break gave him the platform for his powerful serve. In the second Kolar applied greater pressure to earn break points in the fourth game which he was able to convert. As an upset started to seem more likely Kolar’s game dropped in intensity giving Tsitsipas the opportunity to break back. But while he produced moments of great playing, the Greek was not allowed to settle into the game. He saved set points in the second but Kolar fought back to a tie break that Tsitsipas eventually won.

In the third set Kolar prevailed in the tie break. He produced a top-level game that delighted the Paris crowd.

In the fourth set, Tsitsipas found a new gear as he focussed more on what needed to be done and less on berating his mistakes before the world. Although Kolar seemed to be drained, his response was to up his game but Tsitsipas held on to win another close encounter.

On Wednesday the Greek came back from two sets to defeat Italian Lorenzo Musetti in a five-set thriller (5-7, 4-6, 6-2, 6-3, 6-2) that lasted three and a half hours.

Meanwhile former world number 1 and three-time French Open winner Mats Wilander said that Tsitsipas’ backhand play needed to improve as it was holding him back from winning major tournaments.

The Swedish former world champion told Eurosport that while he was impressed with the Greek’s fighting spirit and desire, he felt Tsitsipas was being let down by his backhand.

“It’s simple against Tsitsipas, it’s hard to beat him, but you have to target the backhand of Tsitsipas. The backhand is not progressing. His fighting spirit is, but when the balls are heavy, he is not getting much on it. Kolar was good at targeting it (the backhand),” said Wilander.

Tsitsipas meets Sweden’s Mikael Ymer in the third round on Saturday (Paris time).