Sam Stosur, the defending champion, went out of the US Open with a whimper before a doomed bang in the quarter-finals against Victoria Azarenka, who seems well and truly to have her number.

This was the Australian's seventh straight defeat to the Belarusian, who won Stosur's national Open in February, although she did drop a set this time.

Azarenka breezed to 6-1, before giving up the second in a rousing fight, 4-6, then winning the tie-break in the third.

It was hard to feel confident about her going past the semi-finals, although the same could be said on the other side of the draw, where Maria Sharapova was 4-0 down against Marion Bartoli when rain forced them off on Tuesday evening. They are due to resume on Wednesday.

Stosur, who beat Laura Robson in the fourth round, said she was sad to be going home, happy to have played well after a disastrous start. In contrast, Robson said she could take nothing but disappointment away from their match, even though she rallied at the end.