Poland's Agnieszka Radwanska eased into the quarterfinals when she beat Hungary's Greta Arn of Hungary 6-3, 6-4.

CNN: Nadal wins in Barcelona, Ivanovic out of Stuttgart

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

The match appeared to be plain sailing in the opening stages against the 30-year-old Arn, ranked 104th in the world.

BBC: Venus Williams & Kim Clijsters into US Open round two

Arn led 4-0 and, despite losing momentum, still had a service game to take it to a decider at 5-3.

BBC: Venus Williams & Kim Clijsters into US Open round two

Clijsters had to overcome a wobble in the second set to beat Greta Arn 6-0 7-5 and book her place in round two.

BBC: Venus Williams & Kim Clijsters into US Open round two

The Londoner also came through qualifying at the Pan Pacific Open in Tokyo in September, before losing in the first round to Hungary's Greta Arn.

BBC: Andy Murray and Laura Robson set to play in Hopman Cup

Paraguay's Rossana Neffa-De Los Rios was another comeback winner against German Greta Arn, amd her 0-6 7-6 7-6 won sets up a clash with sixth seed Alexandra Stevenson.

BBC: Farina Elia into quarters

The New York Times on Tuesday printed text of a letter to his clients from Arn Tellem, one of the most powerful agents, urging Hunter's removal next month, and others will likely follow.

WSJ: Hunter fires family members from NBA players union