A fourth-seeded tandem of Russians Ekaterina Makarova and Elena Vesnina vanquished the unseeded Americans in 7-6 (7-5), 6-4 fashion on an extremely hot day in New York City. Serena had back-to-back double faults to end the match.
The sisters are two-time U.S. Open champs and own 13 Grand Slam doubles titles overall.
Makarova and Vesnina were this year's runners-up at the Australian Open and captured the French Open last year. Vesnina was also a Wimbledon doubles runner-up in 2010.
The left-handed Makarova is into the quarterfinals in the women's singles draw here in Flushing.