Indian tennis player Rohan Bopanna's Pakistani doubles partner Aisam-ul-Haq Qureshi says the pair will have to become mentally tougher to produce knockout performances that are required to win Grand Slams.

Aisam and Bopanna earlier this week lost to world number one Bob and Mike Bryan 6-7 (7-4), 6-3, 7-6 (7-3) in the French Open quarter-finals in a match spread over two days.

The defeat, according to Aisam, taught him a lesson and issued a reminder that he needs to improve on clay which, for him, is the most challenging surface.

"Looking back at the quarter-final, we should've done a few things differently," Qureshi said in an interview to the The Express Tribune newspaper.

"Clay is not our favourite surface but we got used to it this year and if we look at our performances in the first three rounds, we won our matches convincingly.

"I feel that we broke down in the middle after winning the first set. And by the time we got our focus back, it was too late. We missed a few crucial points and that proved our downfall. I wish we were mentally stronger than them. We defeated them last year so it's not like we are less capable than them," he explained.

The quarter-final exit was Aisam's best performance on clay so far. He managed to reach the second round with Bopanna at Roland Garros last year and picking up from there, Aisam remained content with what he managed this year.

The pair outplayed Italy's Andreas Seppi and Simon Vagnozzi in a first-round demolition before winning a three-set match against Argentina's Maximo Gonzalez and Japan's Kei Nishikori in the second round.

Another straight-set win over Andrey Golubev and Denis Istomin booked their last-eight match against the Bryan brothers, the pair who beat the sub-continental duo in the US Open final last year.

However, the 31-year-old said he has only positives to take from the French Open as he launches his preparation for Wimbledon that starts from June 20.

"We're taking one step at a time. We will do better at the French Open next year. However, climbing two places in the ATP doubles rankings before Wimbledon is a huge achievement.

"It has given us more confidence which we badly needed."

The duo will now practice in Germany on grass courts for a week before flying to England for Wimbledon.