Serena Williams took a medical timeout because of a problem with her right foot and later double-faulted on the last two points as she and sister Venus Williams lost in the doubles quarterfinals at the US Open. The Williams sisters, owners of 13 Grand Slam doubles titles, were beaten 7-6 (5), 6-4 on Tuesday by the fourth-seeded Russian duo of Ekaterina Makarova and Elena Vesnina. Read more http://espn.go.com/tennis/usopen14/story/_/id/11454052/serena-medical-us-open-doubles-loss