Serena Williams reveals ankle injury fears

Serena Williams has revealed that she felt nervous about an ankle problem during Thursday's win over Maria Jose Martinez Sanchez at the US Open.

The Olympic gold medallist strained her ankle while playing doubles with sister Venus on Wednesday before labouring through her second-round match with the Spaniard.

"I was running for a shot and rolled it," she told reporters. "Story of my ankle life. But it was fine.

"I did a lot of ice and tape, compression to keep the swelling out. I rolled it in Australia so I was a little nervous but it's fine."

Williams, who is looking to win a fourth title at Flushing Meadows, faces Ekaterina Makarova in the third round.