Polish teenager Iga Swiatek shocked top seed and 2018 champion Simona Halep to reach the Roland Garros quarter-finals where she will face Italian qualifier Martina Trevisan as the tournament took another dramatic twist on Sunday.

Swiatek, just 19 and ranked 54 in the world, triumphed 6-1, 6-2 on the back of 30 winners and not allowing 2018 winner Halep a single break point.

"I am surprised I could do this," admitted Swiatek after ending the 17-match winning streak of Halep who was the overwhelming favourite in the absence of 2019 champion Ashleigh Barty and US Open winner Naomi Osaka and the injury-enforced withdrawal of Serena Williams.

It was a stunning turnaround for the Pole who won just one game against Halep at the same stage in Paris last year, getting swept off court in just 45 minutes.

"Last year I wasn't experienced enough, it was my first match in a big stadium so I was a little stressed, but now I can handle the pressure."

No problem: Rafael Nadal celebrates after defeating Stefano Travaglia in the third round
No problem: Rafael Nadal celebrates after defeating Stefano Travaglia in the third round AFP / Thomas SAMSON

Swiatek swept through the opening set in just 23 minutes, firing 17 winners to Halep's four.

The teenager tightened her grip, breaking in the first game of the second set with Halep having to fight off four break points in the third game to stay afloat.

Swiatek's assault continued against a player who arrived in Paris with claycourt titles in Prague and Rome.

Halep, 29, saved five more break points in the fifth game but a weary forehand drifted wide and her Polish opponent was 4-1 up with the cushion of a double break.

She took victory on a second match point, ending the tie in 68 minutes.

Shock victory: Poland's Iga Swiatek celebrates defeating Simona Halep
Shock victory: Poland's Iga Swiatek celebrates defeating Simona Halep AFP / MARTIN BUREAU

"I didn't lose that match, Iga won it," said Halep.

Swiatek's victory was quickly followed by another surprise when Trevisan registered a 6-4, 6-4 victory over fifth seed Kiki Bertens, a semi-finalist in 2016.

The 26-year-old Trevisan, ranked 159, is the first qualifier to make the last eight since Yaroslava Shvedova in 2012.

Trevisan saved two match points in her win over Greek 20th seed Maria Sakkari.

Sunday shocker: Italy's Martina Trevisan  celebrates
Sunday shocker: Italy's Martina Trevisan celebrates AFP / Anne-Christine POUJOULAT

"I'm living in a dream," said the Italian whose other appearance in the main draw of a major came at the Australian Open in January.

Sunday's early shocks mean that only four seeds remain in the women's draw -- third seed Elina Svitolina, fourth-seeded Australian Open champion Sofia Kenin, two-time Wimbledon winner Petra Kvitova, seeded at seven, and Tunisia's Ons Jabeur, the 30th seed.

Rafael Nadal and Dominic Thiem take great leaps into the unknown when they tackle opponents ranked outside the top 200 for places in the quarter-finals.

Second seed Nadal, the 12-time champion, faces world number 213 Sebastian Korda whose father Petr was runner-up in 1992.

World number three and US Open champion Thiem, runner-up to Nadal for the last two years, meets Hugo Gaston, ranked at 239.

Korda, 14 years younger than 19-time Slam winner Nadal, admits that he was in awe of the great Spaniard growing up.

"I named my cat Rafa after him. That says a lot about how much I love the guy," said 20-year-old Korda who came through qualifying.

Gaston is the only French player left in the men's tournament from the 18 who started out.

Having defeated 2015 champion Stan Wawrinka in five sets in the third round, the wildcard has to take on Thiem.

Austrian Thiem, like Nadal, has reached the last 16 without dropping a set and is looking to make the quarter-finals for a fourth successive year.

Should Nadal defeat Korda and register his 97th win in Paris, he will face either German sixth seed Alexander Zverev or 19-year-old Jannik Sinner of Italy who is the youngest man in the last 16 since Novak Djokovic in 2006.

Sinner hasn't dropped a set in three matches.

Zverev, buoyed by making his first Grand Slam final in New York last month, is in the fourth round for a third straight year.

The day's other last 16 match features Diego Schwartzman, the 12th-seeded Argentine who stunned Nadal in Rome on the eve of Roland Garros. He faces 46th-ranked Lorenzo Sonego of Italy who is in the fourth round of a major for the first time.

Svitolina, twice a quarter-finalist, meets France's Caroline Garcia.

Argentine qualifier Nadia Podoroska, ranked 131, faces number 114 Barbora Krejcikova of the Czech Republic who has four doubles titles at the majors.