Carlos Alcaraz fought past American Ben Shelton in a tight four-set match to reach the French Open quarterfinals on Sunday, while Iga Swiatek staged a comeback to defeat Elena Rybakina and keep her bid for a fourth straight title alive.

Reigning champion Alcaraz clinched a 7-6 (10/8), 6-3, 4-6, 6-4 victory after three hours and 19 minutes on Court Philippe Chatrier to book a Last-Eight berth for a fourth straight year.

Alcaraz will take on Tommy Paul in the quarterfinals, after the 12th seed saw off Australia's Alexei Popyrin 6-3, 6-3, 6-3.

"Today I fought against myself in my mind," he said.

"In some moments I was mad, I was thinking not very good things. But I'm really happy that I didn't let the bad thoughts play against me... I tried to calm myself down and keep going."

The four-time Grand Slam champion saved three set points in a dramatic opening-set tie-break before clinching it himself on his second.

He crucially then saved six break points in a marathon first game of the second set, before going on to win it courtesy of a break in the eighth game.

American 13th seed Shelton deservedly got a set on the board to extend the match, but Alcaraz quickly bounced back with an early break in the fourth.

The second seed saw a match point come and go in the ninth game of the set, but he quickly brought up another one on his own serve and took the opportunity with a trademark forehand winner.

Lorenzo Musetti continued his rich vein of form with an impressive 7-5, 3-6, 6-3, 6-2 success against Danish 10th seed Holger Rune in the night session.

The Italian eighth seed, who reached at least the semi-finals in clay-court Masters events in Monte Carlo, Madrid and Rome, will face Frances Tiafoe in the last eight.

American 15th seed Tiafoe booked a place in his first-ever French Open quarterfinal with a 6-3, 6-4, 7-6 (7/4) win over unseeded German Daniel Altmaier.

Four-time Roland Garros champion Swiatek, who has been struggling for her best form and has not reached a final since winning the title last year, was in serious trouble when trailing 2-0 to Rybakina in the second set.