The 14th seed slumped to a shock 4-2 defeat against world number 105 Hamilton, who now plays fellow qualifier Josephus Schenk.

BBC: SPORT | Other Sport | Darts | Taylor and Lloyd into last eight

But their compatriot Flavia Pennetta made a shock early exit as the 19th seed lost 6-3 1-6 6-2 against Russian qualifier Nina Bratchikova.

CNN: No. 1 Wozniacki wins Melbourne opener

In other matches, top seed Maria Sharapova suffered a shock 6-2 7-5 defeat by Hungarian veteran Greta Arn.

BBC: Heather Watson loses to Shuai Peng in Auckland quarters

Earlier, third seed Nicolas Almagro made a shock exit when he was beaten in straight sets by Russia's Mikhail Youzhny in their second round match.

CNN: Ivanovic follows Serena in crashing out

There was a shock on Court 13, where seventh seed and Australian Open finalist Fernando Gonzalez of Chile made an early exit to Russia's Teimuraz Gabashvili.

BBC: Nadal limps past wildcard Jones

There was a shock on Court 13, where 31st seed Michaella Krajicek, who thrashed Britain's Katie O'Brien in the previous round, beat eighth seed Anna Chakvetadze in a marathon three-set battle.

BBC: SPORT | Tennis | Jankovic survives Safarova battle

The 30-year-old produced a massive shock, knocking out local favorite and 24th seed Julia Georges in a 7-6 (10-8) 6-0 victory.

CNN: Wild card Monfils takes center stage

That pair were joined in the quarterfinals by three other Spaniards, with Albert Montanes producing the shock of the day by dumping out fourth seed Marin Cilic 6-4 6-4.

CNN: Superb Nadal powers into quarterfinals

Elsewhere, French eighth seed Jo-Wilfried Tsonga suffered a shock defeat by Jerzy Janowicz, going down 6-4 7-6.

CNN: Injured Murray to miss French Open?

There was a shock at the WTA Aegon Classic in Birmingham as top seed Francesca Schiavone lost 7-5, 6-4 to Japan's Miskai Dothe.

CNN: Top seed Murray crashes out at Queen's

And there was a third shock when yet another Russian, French Open champion and fifth seed Svetlana Kuznetsova lost 7-5 4-6 6-3 to Germany's Andrea Petkovic.

CNN: Safina and Venus sent crashing out in Tokyo

Two seeds suffered shock defeats as Spain's Nicolas Almagro, the No. 10 seed, was knocked out by Austrian Jurgen Melzer.

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However, there were some shock results on the first day at Roland Garros, with defeats for 10th seed Victoria Azarenka and Spanish 20th seed Maria Jose Martinez Sanchez.

CNN: Kuznetsova through after shaky start

Fifth seed Li Na, who won at Roland Garros in 2011, suffered a shock defeat against Jelena Jankovic.

CNN: Nadal survives scare at Rome Masters