Aggression proves the key as O'Brien shines

The British No 2 joined No 1 Elena Baltacha in going through after a straight sets win over Patricia Mayr.

The 23-year-old won 6-3 6-3 to progress past the first round of a grand slam for just the second time in her career.

O'Brien's best result at a major was reaching the second round at Wimbledon in 2007 and a confident display against a player ranked three places behind her in 90th ensured she would at least match that.

A difficult task awaits in the next round where she will play eighth seed Jelena Jankovic, who beat Monica Niculescu 6-3 6-0.

O'Brien admitted she had put pressure on herself. "I knew it was a good opportunity. I had a good draw and I knew I had to go out and compete," she said.

"I think I dictated the play and made her do the running and wore her down. I think it was a good solid performance.

"I'm trying to add aggression to my game. There were a few points I was disappointed with where I let her in, but the first match of a grand slam is always tough. I think I settled down well though. I felt really good on court."

O'Brien broke her Austrian opponent in the fifth game to go 3-2 ahead and then, with Mayr serving to stay in the set, broke again to take the advantage.

Mayr broke early in the second set but from there the Austrian's serve let her down.

O'Brien pounced on the opportunity and broke on three consecutive occasions to surge ahead before wrapping up the match when Mayr dumped a forehand into the net.

World No 1 and defending champion Serena Williams maintained her remarkable unblemished record in the first round of grand slams with a 6-2 6-1 win over Urszula Radwanska.

Men's world No 1 Roger Federer battled back from a set down to overcome Igor Andreev.

The Swiss star was sloppy as the Russian's big hitting and aggressive style repeatedly forced him into errors. It was the first time in 25 first-round grand slam matches Federer had been taken past three sets but he eventually wore down his opponent 4-6 6-2 7-6 (7/2) 6-0.