{blackbabes} Serena vows to work 'five times harder'

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Paris (AFP) - Serena Williams was left furious following her bombshell second round exit from the French Open but vowed to work "five times harder" to repair her bruised status as the world's best player.

To cap off a miserable day for the Williams' family, sister Venus was also knocked out as the two American superstars lost at a major on the same day for only the fourth time.

The top seed and 17-time Grand Slam winner lost 6-2, 6-2 to Spanish world number 35 Garbine Muguruza while Venus went out 2-6, 6-3, 6-4 to Slovak teenager Anna Schmiedlova.

"Obviously I'm super disappointed and, you know, it's hard. I worked really hard. But hey, maybe I can do better. I know for a fact I can work harder," said defending champion Serena.

"I know for a fact I can play so much better than I did today, so it's a double-edged sword.

"If I couldn't play better I would be, I think, even more disappointed. But I know I can, so I know I have something to look forward to," added Williams who failed to reach the second week of a Grand Slam for the first time as top seed.

"I will have to work five times as hard to make sure it doesn't happen again," added the 32-year-old American who suffered her only Grand Slam first round loss in Paris in 2012.

It was the earliest exit for a defending champion at Roland Garros since 2005 when Anastasia Myskina of Russia went out in the first round.

With the defeat the women's draw has been blown wide open as Williams joins second seed Li Na of China on the list of top casualties to crash out.

It was the first time in the Open Era that the top two seeds had failed to get past the second round at a Grand Slam event.

"It was one of those days. You know, you can't be on every day, and, gosh, I hate to be off during a Grand Slam," added Williams.

"It happens. It's not the end of the world. It is what it is," said Serena who won 11 titles last year including the French Open and US Open.

For Muguruza, it was the highlight of her career.

"Im very happy, very excited. It's my biggest win so far, so amazing," said the Spaniard.

"I played her I think two years ago and was horrible, because I was so nervous so I said, 'okay, this time I'm not going to think I'm playing against Serena, I'm going to do what I have to do'. That's what I was thinking all the match."

Defeat for Venus, the 29th seed, meant she has now failed to get beyond the second round in Paris on her last three visits.

At 33, the seven-time Grand Slam champion who came closest to winning the French Open in 2002 when she lost in the final against Serena, came into the tournament as the second oldest player in the draw.

The five-time Wimbledon champion can now look ahead to the grass court season, a surface more suited to her game.

"Wimbledon is the next focus. I've just got to get on the court and start grinding." said Venus.

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