Sharapova stretched as she reaches semi-finals

Nadia Petrova took Maria Sharapova close in their quarter-final encounter at the US Open, but the top seed had just enough to edge past her Russian counterpart.

Sharapova, who had not lost a set prior to this match, took two-and-a-half hours to clinch a 7-5 4-6 6-4 victory over the ninth-seeded Petrova.