Laura Robson of Britain congratulates Samantha Stosur (right) of Australia after their women's singles match at the US Open tennis tournament in New York on Sunday.

New York - Defending champion Samantha Stosur ended the giant-killing run of 18-year-old Briton Laura Robson with a hard-fought 6-4, 6-4 win in the fourth round of the US Open on Sunday.

The Australian came from a break down to win the first set and held off a late fight-back by Robson in the second to advance to the last eight after one hour and 38 minutes.

Robson had beaten Kim Clijsters and Li Na to make the fourth round but Stosur was the more consistent as she took the first set and led 5-2 in the second.

The Briton battled back, saving eight match points in the process, but Stosur broke her again to set up a likely clash with top seed Victoria Azarenka. - Reuters