Playing at Roland Garros was the right call, admits jubilant Del Potro

Juan Martin del Potro is surprised to have reached the French Open semifinals after being unsure at one stage if he would even participate in Paris.

The world number six last played in the semifinals at Roland Garros in 2009, but has since been hindered by a series of wrist injuries, while a groin issue put his participation in this year's tournament in doubt.

But, Del Potro has rediscovered his best form on clay, defeating Marin Cilic in four sets in the quarter-finals to set up a clash with Rafael Nadal.

READ: Emotional Del Potro ends wait for Roland Garros semifinal

And given that he could have skipped a grand slam he has readily missed in the past, Del Potro is relieved he made "the right decision" over playing in the French capital.

"I'm feeling so, so happy to have made the right decision to play here. I am doing well. Of course, I didn't expect to get into the semi-finals a couple of weeks ago. But now I'm here and I'm still alive. My physical [condition] is good and hopefully I can be ready for [Friday]," he said.

Del Potro could not have been handed a tougher opponent in the last four, though he accepts that he is playing in an era where all-time greats dominate in the latter stages of major tournaments.

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"I thought that after nine years I would play a different [player], not Rafa or Roger [Federer, as in 2009]. But, all of my semi-finals in grand slams were against them," he said.

"The last one, in the US Open, I lost against Rafa. In Wimbledon, I lost against [Novak] Djokovic. Here, with Federer. It's a big challenge to play them in a grand slam."

"They show how good they are at playing grand slams because, after 10 years, they are still fighting to win these kind of tournaments. It's amazing for the tennis world."

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Meanwhile, the defeated Cilic is now full of optimism for the remainder of the year - starting with a switch of surface as he focuses on the grass-court season.

"I'm glad that the knee injury is behind me. I'm feeling physically well. I played good tennis here and played several matches," he said.

"In the end, results wise, it's not bad to reach the quarters again, here, at French Open. It's looking good for the grass-court season. I'm looking forward to playing [at Wimbledon] but still taking it step by step."