Laura Robson goes out fighting as Stosur edges home

Defending champion sees off 18-year-old Briton who shows spirit but inexperience

Laura Robson's great American adventure is over. Having beaten two Grand Slam champions in her previous two matches, the 18-year-old Briton was unable to add a third to her list of victims when she was beaten 6-4, 6-4 by Sam Stosur in the fourth round of the US Open here last night.

If Robson did not play as consistently well as she had in beating Kim Clijsters and Li Na, there was certainly no disgrace in losing to the defending champion. Stosur, the world No 7, is one of the best athletes in the women's game. When she does not allow nerves to get the better of her, as she has on occasions in the past, the 28-year-old Australian can be a match for anybody.

Even here, nevertheless, Stosur needed nine match points before securing victory in a tense finale. In the quarter-finals she will now meet the winner of last night's later match between the world No 1, Victoria Azarenka, of Belarus, and Georgia's Anna Tatishvili.

Although Robson made too many unforced errors – 41 to Stosur's 24 – the Briton was right to go for her shots. Although her movement around the court is much improved this summer, Robson's great strengths are her powerful ground strokes and her big leftie serve. There were times when Stosur had difficulty coping with the weight of her opponent's shots, though there were also periods of the match when Robson struggled to find her range.

Nevertheless, Robson's performances here have established her as a major talent in the world game. She is already the youngest player in the world's top 100 – she will not be 19 until January – and her results here will see her climb about 10 places from her current position at No 89 in the rankings.

The first British woman to play in the fourth round of a Grand Slam tournament since 1998 and the first to reach the fourth round here since 1991, Robson was attempting to become the first to play in a Grand Slam quarter-final since Jo Durie at Wimbledon in 1984. Durie was also the last British woman to reach the last eight here, in 1983, when she went on to reach the semi-finals.

Robson's story has caught the imagination of the New York public and she had good support in Louis Armstrong Stadium, the second of the show courts. The 2008 junior Wimbledon champion has coped well with the hot and humid conditions here, but both players were no doubt grateful that at 25C the temperature was down several degrees on the previous day.

Robson drew first blood, breaking in the third game with a thumping cross-court backhand, but from 40-15 up in the next game the Briton dropped her own serve. At 4-4 Robson failed to take two break points, for which she was quickly made to pay. She saved one set point in the following game when Stosur hit a forehand long, but on the second the teenager hit her first double fault of the match.

It was a disappointing way to hand Stosur the advantage, but Robson came out fighting at the start of the second set, winning the first two points with crashing returns of serve. She forced three break points two games later, but Stosur defended them superbly and went on to break for a 3-1 lead.

Robson, however, was not done yet. When she served to stay in the match at 2-5 she showed her great competitive spirit, saving five match points in a 19-minute game of eight deuces.

In the following game Robson survived two more match points, firstly when Stosur hit a backhand long and then with a huge forehand return, and went on to break serve. When she served at 4-5 Robson went 15-40 down and saved yet another match point. On Stosur's ninth, however, the Australian was relieved to see a Robson forehand sail beyond the baseline.