Defending champion Garbine Muguruza was unhappy with a "really tough" crowd after defeat by home favourite Kristina Mladenovic at the French Open.

The Spaniard, 23, lost 6-1 3-6 6-3 on a packed Suzanne Lenglen Court which gave its full backing to Mladenovic.

Seven-time Grand Slam winner Venus Williams' defeat by Swiss Timea Bacsinszky means a new major champion will be crowned in Paris on Saturday.

"It's a very painful defeat here in the French Open," said a tearful Muguruza.

"The crowd was really tough today. I can't really understand. I don't know how to explain.

"If you had been in my shoes on the court, I think you would have understood.

"I don't know what people were expecting. I'd rather not say anything more."

Mladenovic, 24, served 16 double faults but came through amid a raucous atmosphere on the second show court at Roland Garros.

"I don't think that they crossed the line," she said of the crowd.

"I mean, I noticed once - and I think it was bad - when they kind of screamed between her first and second serve, but that's because they thought it's a double fault because the first serve was a let or something.

"But that's the only thing that happened. Otherwise, they were quite fair."

No Frenchwoman has won the title at Roland Garros since Mary Pierce in 2000.

Thirteenth seed Mladenovic joins Bacsinszky, Denmark's Caroline Wozniacki and Latvian Jelena Ostapenko in the last eight, with only three of the top 10 seeds still in the draw.

Muguruza, 23, left her media conference briefly because she was so upset, before returning to reveal she was glad to relieve the pressure of being French Open champion.

"I love this tournament no matter what happens," said Muguruza, who claimed not to have been distracted by Mladenovic's cries of "Forza!" after the Spaniard's errors.

"I'm going to be super happy to come back.

"Everybody is going to stop bothering me asking me about this tournament, so it's going to be a little bit like, 'Whew, let's keep going.'"

Timea Bacsinszky knocked Venus Williams out of the French Open for the second successive year

Second seed Karolina Pliskova, third seed Simona Halep and fifth seed Elina Svitolina will aim to reach the quarter-finals when they play their fourth-round matches on Monday.

Pliskova and Svitolina won their rain-delayed third-round matches on Sunday, while former world number one Wozniacki reached the last eight.

Williams, the 10th seed, fought back from 5-1 down to take the opening set against Bacsinszky.

But 27-year-old Bacsinszky broke Williams' serve in the first game of the second set as she won 12 of the last 15 games in the match.

Wozniacki, 26, reached the quarter-finals at Roland Garros for the first time since 2010 with a 6-1 4-6 6-2 win over Russia's Svetlana Kuznetsova, the eighth seed and 2009 champion.

Pliskova, the Czech, beat Carina Witthoft of Germany 7-5 6-1, while Svitolina of Ukraine overcame Poland's Magda Linette 6-4 7-5.