���˿���

Serena Williams has beaten her sister Venus at the US Open, taking her one step closer to a calendar Gram Slam.

She needs just two more victories to be the first player to win all four majors in the same year since Steffi Graf did back in 1988.

Serena held her nerve against her sister to win 6-2 1-6 6-3 at Flushing Meadows in New York.

The world number one will now play Italian Roberta Vinci in the semi-finals on Thursday.