Spain's Rafael Nadal clenches his fist after winning his fourth round match of the French Open tennis tournament against Sebastian Korda of the US (not in frame) at the Roland Garros stadium in Paris, France, Oct 4, 2020. (MICHEL EULER / AP)

PARIS - Both of last year's finalists, Rafael Nadal and Dominic Thiem, advanced into the quarterfinals at the French Open on Sunday, but in very different ways.

The 12-time champion Nadal only dropped four games to complete a 6-1, 6-1, 6-2 win over American qualifier Sebastian Korda, Zverev had to escape a five-set thriller to overcome local star Hugo Gaston 6-4, 6-4, 5-7, 3-6, 6-3.

I'm in the quarterfinals without losing a set and having very positive scores. I can't complain at all, so I'm happy for that.

Rafael Nadal, Spanish tennis player

Meanwhile, some big names saw their title race end in Paris on Sunday, such as women's top seed Simona Halep, whose 17-game winning streak was snapped by Poland's Iga Swiatek 6-1, 6-2 in an unexpectedly one-sided match, and sixth-seeded Alexander Zverev, who admitted he played despite being sick and suffered a 6-3, 6-3, 4-6, 6-3 defeat to Italy's teenager Jannik Sinner.

ALSO READ: Teenager Sinner stuns 11th seed Goffin, Halep claims 15th win

Defending champion Nadal converted eight of his 11 break points to breeze past the son of 1998 Australian Open winner Petr Korda, to reach a record-breaking 14th quarterfinal at Roland Garros.

"I'm in the quarterfinals without losing a set and having very positive scores," Nadal said, "I can't complain at all, so I'm happy for that."

But for the 20-year-old Korda, to play in the second week of a grand slam has already been a good run, especially having the chance to play with a tennis great, whom he considers as his idol, in the round of 16.

"Ever since I was a kid, I mean, I was in love with him and everything about him. I would watch every single match. Doesn't matter who he was playing or what tournament he was playing. He was the guy for me," said the 213th-ranked Korda.

Nadal has recorded 97 victories in the clay major since his title-winning debut in 2005, and has only lost two matches here in the past 15 years. He will next face another young player - 19-year-old Sinner, who defeated a sick Zverev, to become the youngest men's Grand Slam quarterfinalist since Novak Djokovic in Paris in 2006.

READ MORE: Ruthless Nadal charges into French Open last 16

Zverev admitted after the match that he was struck by illness after his previous round's clash against Marco Cecchinato, which aroused questions on whether he should have been allowed to continue to play on Sunday.

"I am completely sick after the match with Cecchinato in the night. I can't really breathe, as you can hear by my voice," said Zverev.

Germany's Alexander Zverev serves against Italy's Jannik Sinner (not in frame) in the fourth round match of the French Open tennis tournament at the Roland Garros stadium in Paris, France, Oct 4, 2020. (CHRISTOPHE ENA / AP)

The German star's last COVID-19 test was carried out on Sept 29 and the result was negative, as revealed by a statement from French Tennis Federation (FFT), and he should have received a reminder for his next test, which has to be carried out within five days of the previous result.

Two-time finalist Thiem survived a scare from French wild card Gaston, who already clinched a shocking win in the third-round against former champion Stan Wawrinka.

World No. 239 Gaston came to Roland Garros without a tour-level win but utilized his well-rounded skills to produce a fairy tale run.

"I think it was an amazing match by both of us," said the third seed Thiem. "Haven't seen for a very long time a player with such big touch in his hands. His drop shots are just from another planet, I was sprinting like 400 times to the net. All the credit to him."

READ MORE: Thiem claims US Open title after thrilling fightback

The newly-crowned US Open champion will play 12th seed Diego Schwartzman in the quarterfinals. The world No. 14 dispatched Frenchman Lorenzo Sonego 6-1, 6-3, 6-4 to reach the fourth round.

Austria's Dominic Thiem serves against France's Hugo Gaston (not in frame) in the fourth round match of the French Open tennis tournament at the Roland Garros stadium in Paris, France, Oct 4, 2020. (ALESSANDRA TARANTINO / AP)

In women's actions, the 19-year-old Swiatek needed just 68 minutes to avenge her exit to Halep last year in Paris at the same stage.

"I don't know what happened actually, I felt like I was playing perfectly, I was so focused in the whole match, even I am surprised that I can do that," said the 54th-ranked Swiatek, who fired 30 winners and won 81 percent of her first serves to wrap up a victory over the two-time Grand Slam winner.

"I wasn't experienced at all then, that was my first match on a big stadium like that, so I was pretty stressed," Swiatek said of her fourth-round loss to Halep last year.

"Since then, I've made huge progress because I've played a few big matches, against Simona, against Caroline Wozniacki and Naomi Osaka, and I think it helped me a lot and now I feel like I can handle the pressure," Swiatek added.

Halep, the 2018 champion, didn't play at her best, especially when facing a firing teenager who combined her drop shot and backhand so perfectly throughout the match.

ALSO READ: Halep firm favorite for French Open after winning streak

"She played unbelievable today and she was everywhere and she hit all the balls in a very strong, very powerful way," the world No. 2 said after the match. "It was a little bit cold and I couldn't be at my best."

"I knew she was going to be aggressive. I knew that she's playing this way. Today it worked really well for her," Halep added. "At this level, nobody surprises anybody anymore because everyone has a big level and it depends on the day that you are."

Romania's Simona Halep reacts after missing a shot against Poland's Iga Swiatek (not in frame) in the fourth round match of the French Open tennis tournament at the Roland Garros stadium in Paris, France, Oct 4, 2020. (MICHEL EULER / AP)

Swiatek is to face another unexpected winner from the fourth round - Martina Trevisan, as the world No. 159 stunned another title favorite Kiki Bertens 6-4, 6-4 in a later match on Court Suzanne-Lenglen.

"I'm living in a dream. I came here two weeks ago to my Roland-Garros qualifying but today I'm here in the quarterfinals," said the 26-year-old Italian qualifier, who hadn't played a Grand Slam main draw before this year's Australian Open, where she suffered a first-round exit.

Ukraine's Elina Svitolina remains as the highest-ranked seeded player after storming to a 6-1, 6-3 victory in just over an hour against local hope Caroline Garcia to secure a spot in the last eight.

The No. 3 seed, who is seeking her maiden semifinal at Roland Garros, will play Argentinian qualifier Nadia Podoroska in the next stage. The world No. 131 Podoroska reached her first career major quarterfinals by defeating Czech Barbora Krejcikova 2-6, 6-2, 6-3.