Laura Robson's amazing run at the 2012 US Open has finally come to an end, after the British teenager was beaten in straight sets by seventh seed and defending champion Samantha Stosur. Robson lost 4-6, 4-6, in 98 minutes.

Laura Robson

Robson, 18, engineered remarkable wins over former World No 1 and three time US Open champion Kim Clijsters in the second round and ninth seed and 2011 French Open champion Li Na in the third, to follow her first round win over unseeded American Samantha Crawford. The Melbourne-born Robson is now the first British woman to reach the fourth round of a Grand Slam in 14 years.

The youngster put up an impressive fight against her Australian opponent, forcing the defending champion to as many as nine match points before finally succumbing. Stosur relied on her strong serve and clean groundstrokes and also benefitted from the occasional poor shot-making of her opponent.

The match began with the Brit claiming a break point in the third game, taking a 2-1 lead to serve in the first set. She should have closed out her next service game - leading at 40-15 - but Stosur turned up the pressure a notch, winning eight consecutive points to reclaim the early break. A string of unforced errors from Robson didn't help her cause and from a golden chance to go 3-1 up, the unseeded challenger found herself 2-3 down.

Samantha Stosur

The second set was equally hard fought and any expectations Stosur may have had of having broken her opponent's will were swiftly dismissed after Robson fought to remain in the match despite going 1-3 down. The Australian, however, managed to step up through the gears once more, both forcing errors and benefitting from unforced ones, to claim the match.

"I'm definitely disappointed," Robson said after the game, "I didn't play as well as I had in my last two matches, although her serve is special and it took a bit of time to get used to. I had too many unforced errors and didn't take my opportunities. I can take away from here the fact that I'm up there with the top girls in terms of level. Going into my next events, that will give a lot of confidence."

Stosur will now play top seed and World No 1 Victoria Azarenka, after the Belarusian swept Georgian Anna Tatishvili aside 6-2, 6-2.

The second quarter final that has been decided will be played between third seed Maria Sharapova of Russia and 11th seed Marion Bartoli of France. Both women were taken to three sets in their respective games, with Sharapova overcoming compatriot and 19th seed Nadia Petrova and Bartoli recovering from dropping the first set to blank 2011 Wimbledon champion Petra Kvitova in the decider.