(CNN) It will be just like old times at the French Open for Roger Federer and Stan Wawrinka, who will meet in the quarterfinals again after completely contrasting victories.

While Wawrinka outlasted Stefanos Tsitsipas in a five-hour, nine minute classic 7-6 (6) 5-7 6-4 3-6 8-6 that left his opponent in tears, the elder Swiss eased past Leonardo Mayer 6-2 6-3 6-3 and still hasn't dropped a set this fortnight.

When Federer, 37, last played at Roland Garros in 2015, he fell to Wawrinka in the last eight and his pal went on to win the second of three grand slam titles.

"I hope he's not at the level of '15, but we'll find out, because there he was crushing the ball," Federer, the 2009 champion, told reporters Sunday before Wawrinka's marathon concluded. "It was unbelievable.

Federer might get his wish. As strong as Wawrinka is, the 34-year-old will somehow have to recover after the draining win over the young Greek star who has taken the tennis world by storm.

All three of Wawrinka's victories over Federer have come on clay, although the latter owns a winning 22-3 record overall.

"I'm getting old and older and older," said Wawrinka. "But I love that kind of challenge and I'm going to try to do my best to play my best tennis.

Tsitsipas stunned Federer in the fourth round of the Australian Open in January, on a day when the 20-time major winner went an incredible 0-for-12 on break points.

Photos: Wawrinka battles past Tsitsipas Stan Wawrinka was in jubilant mood at the French Open Sunday. He outlasted Stefanos Tsitsipas in a five-hour classic. Hide Caption 1 of 10 Photos: Wawrinka battles past Tsitsipas Wawrinka, the 2015 champion, fended off 22 of 27 break chances against the young Greek star who has taken the tennis world by storm. Hide Caption 2 of 10 Photos: Wawrinka battles past Tsitsipas Wawrinka now meets fellow Swiss Roger Federer in the quarterfinals.

Two days after contesting his 400th grand slam match, Federer won to become the oldest men's quarterfinalist at Roland Garros since 1971. Hide Caption 3 of 10 Photos: Wawrinka battles past Tsitsipas Federer eased past Leonardo Mayer in straight sets five years after the Argentine held match points on the Swiss in Shanghai. Hide Caption 4 of 10 Photos: Wawrinka battles past Tsitsipas When Federer and Wawrinka met in the 2015 quarterfinals, Wawrinka won and then went on to win the title over Novak Djokovic. Hide Caption 5 of 10 Photos: Wawrinka battles past Tsitsipas The winner of that match could face Nadal in the semifinals. The record 11-time champion continued to progress, beating Juan Ignacio Londero in straight sets. Hide Caption 6 of 10 Photos: Wawrinka battles past Tsitsipas In the women's draw, last year's finalist Sloane Stephens topped former champion Garbine Muguruza in straight sets. Hide Caption 7 of 10 Photos: Wawrinka battles past Tsitsipas After going 0-4 in her previous grand slam fourth rounds, Petra Martic broke through by beating Kaia Kanepi in three sets. Hide Caption 8 of 10 Photos: Wawrinka battles past Tsitsipas Marketa Vondrousova, 19, also reached her first grand slam quarterfinal -- a day after her fellow Czech Katerina Siniakova stunned world No. 1 Naomi Osaka. Hide Caption 9 of 10 Photos: Wawrinka battles past Tsitsipas Like Martic and Vondrousova, Johanna Konta also flourished on the clay heading into Roland Garros. When she made the quarterfinals, she became the first British woman to do so in Paris since Jo Durie in 1983. Hide Caption 10 of 10

Break points key

On Sunday on Suzanne Lenglen court in hot and blustery Paris, it was Tsitsipas who struggled on break chances, going 0-for-8 in the final set and 5-for-27 overall.

He was left devastated in defeat.

"Never experienced something like this in my life," the sixth seed said. "I feel very disappointed at the end. Long time since I cried after a match, so emotionally wasn't easy to handle.

"It's the worst feeling ever. Especially when you lose. You don't want to be in my place."

Wawrinka creaked in the final set but never cracked. The lone break points Tsitsipas faced in the fifth set, meanwhile, came in the last game.

In a tussle filled with breathtaking strikes, Wawrinka's finish was both sublime and atypical.

With the players taking turns ripping one-handed backhands and going to the net throughout the marathon -- particularly Tsitsipas -- it was defense that officially got Wawrinka over the finish line.

His backhand slice from well outside the tram lines angled just enough to catch the outside of the line on a second match point. Chair umpire Renaud Lichtenstein had a closer look at the mark and confirmed the ball was good.

Fittingly the two men embraced at the net seconds later, to cap the fourth-longest match in tournament history.

How sweet it was for Wawrinka, who thought his career might be over following a knee injury in 2017 that necessitated multiple surgeries.

Even though Tsitsipas failed to convert many of his break chances -- "so many break points, so many," he lamented -- it would be harsh to criticize the 20-year-old.

He dived for volleys like Boris Becker in his heyday, and rallied impressively after dropping the third set.

Wawrinka's famous backhand, however, was in full flow. He saved a set point in the opening tiebreak with a backhand passing shot and broke Tsitsipas to temporarily stay in the third set with another glittering pass.

In the third set, at 4-5, one of the five set points he saved in the game came when he ran Tsitsipas all over the court before gently stroking a drop shot that clipped the net.

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Light hearted moment

The pair took turns applauding each others' shots, and early in the fifth in a light-hearted moment, one fan shouted out, "I love you, Stan." Wawrinka smiled and acknowledged the spectator.

Seconds later, seemingly the same fan shouted, "I love you," to the Greek who was contesting just the second fifth set of his blossoming career. He also smiled.

"This kind of atmosphere, for sure, I enjoyed," said Wawrinka. "I enjoy a lot. That's the reason why I still play tennis, and that's the reason why I'm practicing every day to try to win big matches like that.

"So for sure when I'm on the court I try to enjoy and remember also everything I have done to be here."

If you were an admirer of one-handed backhands -- considered more elegant than the two-hander but diminishing in use -- you would have enjoyed seeing Wawrinka, Tsitsipas, Federer and Mayer in action. It certainly pleased Federer.

"It's good to see," said Federer. "You feel more free by hitting with the one hand."

Roger Federer (blue shirt) and Stan Wawrinka will meet in the French Open quarterfinals. When they played in 2015 in Paris, Wawrinka won.

Rafael Nadal possesses a two-handed backhand that has shown more zip from the baseline in recent years and the King of Clay, like Federer, cruised into the last eight by ousting Mayer's fellow Argentinean Juan Ignacio Londero 6-2 6-3 6-3.

This after the 11-time French Open winner dropped a set against David Goffin in round three.

While the top 10 men's seeds in the draw had all advanced to the fourth round, the same couldn't be said in the women's draw.

On Saturday, two more contenders exited in world No. 1 Naomi Osaka and 23-time grand slam winner Serena Williams in a double shock. Such is the depth that any player can beat just about anyone else on any given day.

But another of the contenders, last year's finalist Sloane Stephens, overturned an early break deficit to overcome former champion Garbine Muguruza 6-4 6-3.

Petra Martic and Marketa Vondrousova aren't as well known as Williams and Osaka to casual supporters but they enjoyed fruitful French Open buildups.

Konta makes history

Both advanced to maiden grand slam quarterfinals -- and will face off Tuesday -- after Martic came back to beat Kaia Kanepi 5-7 6-2 6-4 and Vondrousova brushed aside Anastasia Sevastova 6-2 6-0.

Jo Konta became the first British woman to make the quarterfinals at Roland Garros since Jo Durie in 1983 by beating Donna Vekic 6-2 6-4.

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Konta had never won a match at the tournament prior to this year, but like Martic and Vondrousova, flourished on the clay in the last month.

She is returning to some of her best form, having dropped outside the top 45 in April from a career-best fourth after making the Wimbledon semifinals in 2017. That fortnight included Konta beating Vekic 10-8 in a third set in the second round.

Similar to back then at SW19, Sunday's clash between Wawrinka and Tsitsipas was unforgettable.