TENNIS:Belarusian Victoria Azarenka survived a ferocious comeback from defending champion Sam Stosur yesterday to reach the semi-finals and ensure she remains world number one following the years last grand slam.

The pair, two of the biggest hitters in womens tennis, traded blows for nearly two and a half hours in a match of unrelenting tension on a blustery Arthur Ashe Stadium centre court before Azarenka triumphed 6-1 4-6 7-6.

Azarenka, who won her first grand slam title at this years Australian Open, had won her previous six matches against Stosur in straight sets and seemed headed to another easy win when she won the first four games and took the rain-interrupted opening set in just 30 minutes. But Australian Stosur found her rhythm after the 75-minute interruption, landing more of her booming first serves and hitting groundstrokes deeper and with greater conviction. The seventh-seed won the second set then recovered from a break down in the third to draw level and force a deciding tiebreak, which Azarenka won 7-5 after blowing a 4-0 lead.