Defending champion Garbine Muguruza knocked out of the French Open by home hope Kristina Mladenovic

The French player stunned Muguruza with a determined three-set victory

Muguruza was knocked out by home favourite Mladenovic (Getty)

A tearful Garbine Muguruza hit out at the French Open crowd after her title defence ended with defeat by Kristina Mladenovic.

Muguruza, who beat Serena Williams in the final 12 months ago, walked off following the loss wagging her finger at the fans on Court Suzanne Lenglen.

Mladenovic is the great French hope to end their 17-year wait for a home singles champion, and the support was understandably one-sided as they cheered the 24-year-old to a 6-1 3-6 6-3 victory.

But Muguruza felt it went too far, saying: "I think the audience was really tough today.

Muguruza was left in tears at the end of the match (Getty)

"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."

The 23-year-old's coach, Sam Sumyk, who is French, later took to Twitter to brand the crowd "pathetic", adding "no class".

Mladenovic defended her support, saying: "I lost a final in Stuttgart against Laura Siegemund, a German player, and I thought the crowd was extremely tough there.

"But I didn't make any comments, because from my opinion it's sport. I just think it's normal that it's such an amazing atmosphere.

"That wasn't easy for me either there, because there was lots of noise. I don't think that they crossed the line.

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

Muguruza broke down in tears during her press conference and had to leave the room for a couple of minutes before returning.

It appeared there was no love lost between the players either, with Muguruza asked about Mladenovic's habit of shouting 'forza' in Italian at key moments.

"I think she speaks like 25 languages, I heard," responded Muguruza sarcastically.

Along with intense disappointment, there was also relief for the Spaniard, who has struggled to cope with the expectation since her triumph here last year.

Anointed as the player to take over Williams' mantle, Muguruza has subsequently failed to reach a single final at any tournament.

She said: "I lost confidence, and my opponent was on home turf, so it created a lot of tension. Of course I'm sad. It's a very painful defeat here at the French Open.

"I love this tournament no matter what happens. I'm going to be super happy to come back. It's going to sound weird, but I'm actually happy that this stage of the year is done.

"I wanted to go as far as possible, but even if I didn't, I think I'm going to feel much better now to continue the year, and everybody is going to stop bothering me asking me about this tournament."

Mladenovic has been struggling with a bad back since the eve of the tournament and served 16 double faults.

But ultimately the rest of her game made up for it, although there must be a concern that she has expended too much emotional energy to go all the way.

Muguruza was joined by Venus Williams, Svetlana Kuznetsova and Sam Stosur in exiting the tournament, meaning the women's event will have a new grand slam champion.

Williams, who had been hoping to win the tournament for the first time in the month of her 37th birthday, lost 5-7 6-2 6-1 to Timea Bacsinszky.

It was the second year in a row the Swiss had beaten Williams in the fourth round.

The American said: "I think she just played really well. She had so many answers today. I just give her credit for playing well every point, even in the first set."

Caroline Wozniacki, with two slam finals now the most experienced player left, continued her fine year with a surprise 6-1 4-6 6-2 victory over 2009 winner Kuznetsova, one of the title favourites.

Wozniacki has never been particularly at home on clay and had not made the quarter-finals at Roland Garros since 2010.

Wozniacki is in Paris with NBA star boyfriend David Lee, and she believes happiness off the court is a factor in her form.

The Dane, previously engaged to golfer Rory McIlroy, said: "I think if everything is calm and good in life, it makes it much easier to focus on the court.

"I have great support. I have great people with me here. It's nice to know that they have my back no matter what."

Wozniacki next faces teenage Latvian Jelena Ostapenko, who knocked out Stosur 2-6 6-2 6-4 to reach her first quarter-final.

Four third-round matches were carried over from Saturday, and top-five seeds Karolina Pliskova and Elina Svitolina both moved safely through.