Serena suffers injury scare

New York - Serena Williams has suffered a foot injury scare on the eve of her US Open quarter-final as she played doubles with sister Venus on Tuesday.

World number one and five-time singles champion Williams took an injury timeout to have her right foot and ankle heavily strapped early in the second set of the sisters' quarter-final against Russian pair, Ekaterina Makarova and Elena Vesnina.

Although the 32-year-old did not appear to be in significant discomfort, the American stars still lost 7-6 (7/5), 6-4 to the Russian fourth seeds.

Williams is due to face Italy's Flavia Pennetta on Wednesday for a place in the semi-finals.