Alexei Popyrin could find no way through American iron man Tommy Paul as the Australian men’s challenge at the French Open petered out tamely in the Roland Garros sunshine.

The Aussie men’s No.2 never looked like grasping the opportunity to earn his first grand slam quarter-final date as he succumbed 6-3 6-3 6-3 on Court Suzanne Lenglen in a one-sided fourth-round clash on Sunday.

Outplayed by the world No.12 in all departments, it was a huge let down for 25th seed Popyrin who had been hoping to go at least one round further than last year’s US Open when he had downed Novak Djokovic before falling the round of 16 to Frances Tiafoe.

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The Sydneysider’s exit in one hour 51 minutes meant that only Daria Kasatkina, in her first slam since gaining permanent residency, is now the last Australian standing, as she seeks to get past Russian teenage sensation Mirra Andreeva in Monday’s last-16 clash.

Popyrin had his finest grand slam moment when he beat the mighty Novak Djokovic at the US Open last August in the third round, but couldn’t back up that win when then bowing out to Frances Tiafoe in his first fourth-round date.

Speaking before Sunday’s loss to Paul, Popyrin said things were very different this time as he went into the last-16 “feeling quite good” physically and mentally after winning his three matches in seven hours seven minutes, having spent over three-and-a-half hours less time on court than Paul.

“I know how I’m going to be feeling in the fourth round of a slam now,” said the 25-year-old Sydneysider said before the match.

“Going into the fourth round against Tiafoe, I had no idea how I was going to feel, especially coming off a match like the third round against Novak. You get the emotional highs, then you top that off with the physical stress.

“That’s something I can kind of learn from, which I have.

“But I’m feeling quite good, considering the circumstances of it being a fourth round of a slam, and hopefully I can keep feeling that way.”

Though he took little comfort from the fact that the seemingly tireless world No.12 Paul has played 14 sets over 10 hours and 45 minutes so far.

“I think Tommy’s one of the fittest guys on tour,” said Popyrin.

“The work he puts in the gym, and puts in off the court, I think he’s only going to come out and play normal. For me, it’s very important not to think about the fact that he’s played two five-setters in a row.

“I have to keep focusing on myself, on the way I’ve been playing for the last two weeks and trying to bring that consistent level again. That’s the most important thing for me.”