Serena Williams hit 12 aces Wednesday and repeatedly rocketed her groundstrokes past Vera Zvonareva to win 6-1, 6-0 and reach the Olympic quarterfinals.

Swinging lustily with almost every shot, Williams hit 32 winners to three for the Russian, who also lost when they met in the 2010 Wimbledon final.

The match was played under the Centre Court roof, and the conditions clearly suited the No. 4-seeded Williams. She swept the final 10 games, and fans unfurled U.S. flags when she closed out the victory after just 51 minutes.

Williams has lost only 10 games through three rounds. The third-time Olympian is the winner of two gold medals in doubles and 14 major titles, but she has yet to win a singles medal.