Thanasi Kokkinakis can't help but admire the likes of Novak Djokovic and Rafael Nadal.

Kokkinakis is through to the third round of the French Open after defeating three-time Grand Slam winner Stan Wawrinka in a five-set thriller on Wednesday.

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The Australian will be back at it again when he faces Karen Khachanov on Friday, and after the brutal experience of winning in five sets, he can only be amazed by how Djokovic and Nadal have each won 22 Grand Slam titles with multiple wins in five-set matches over the course of their careers.

“It's just crazy how guys like Djokovic and Nadal have won 20 of these,” Kokkinakis said (via Sportskeeda). “This stuff is so hard, to be honest. To try and win five sets is brutal. It's a pain, especially on clay. It's a massive relief, and then you're, like, s**t, hang on, I have to go again in two days. I'm just going to swear. I'm sorry. It's me.

“This stuff is so hard, so for people watching at home, it's like, ‘oh, you should be able to do that or whatever.' They don't understand how hard it is and how impressive these guys are.”

Kokkinakis has never made it past the third round in any Grand Slam that he's competed in. That could change with a win over Khachanov but for now, he's taking things one match at a time.

“I'm not too sure, to be honest,” Kokkinakis said when asked how far he could go. “I'm taking it one match at a time. I saw my draw. I knew it was tough. It doesn't get much easier from now. I don't know how good I can be or what I can do.

“I'm not trying to put a limit on myself, but what I do know is that I'm going to give myself every chance and see what I can get to.”

If Kokkinakis is to win a first Grand Slam, he will likely have to get past Novak Djokovic as they are on the same side of the draw.