WIMBLEDON, England -- Serena Williams teamed with big sister Venus to win the women's doubles title at the Olympics on Sunday, adding to the singles gold she won on Centre Court at Wimbledon a day earlier.
The American sisters beat Andrea Hlavackova and Lucie Hradecka of the Czech Republic 6-4, 6-4 under the roof on a rainy afternoon at the All England Club. Venus closed out the match with a backhand volley winner after the Czechs saved a pair of match points.
On Saturday, Serena beat Maria Sharapova 6-0, 6-1 for the singles gold. She joined Steffi Graf as the only women to complete the Golden Slam -- winning the Olympics and the four majors.
When the Americans in the crowd at Centre Court broke into a chant of "U-S-A! U-S-A!" as the players left the court, the sisters each pumped their fists, turned around to wave, then slapped a high-five. The medal ceremony had to wait for the outdoor bronze-medal match, which was delayed by rain.
Serena became tennis' first double gold medalist at an Olympics since Venus won singles and doubles at the 2000 Sydney Games. The sisters also won the doubles gold at the 2008 Beijing Olympics.
Now, they each have a record four Olympic tennis gold medals, and the sisters didn't drop a set through their five matches at the London Games.
The Williames also became the first tennis players to win Olympic gold indoors since the 1912 Stockholm Games, a match played in a pavilion on wood courts painted black.
They won the fourth game of the second set at love on Venus' ace, the first of three straight games in which they didn't lose a point.
Serena overcame two break points trailing 1-0 in the second set. She pumped her fist and cheered after a forehand winner down the alley past a poaching Hradecka, who was aggressive at the net all afternoon.
The Czechs held in four of their first five service games, including Hlavackova's first that went to deuce four times before she held to get them on the board and show they weren't intimidated by the American stars.
Venus Williams joins Conchita Martinez of Spain as the only tennis players to win medals at three different Olympics. Martinez's medals all came in doubles -- silver in Barcelona in 1992, bronze at the 1996 Atlanta Games and silver in Athens in 2004.
Gigi Fernandez and current U.S. coach Mary Joe Fernandez are the only others to win back-to-back Olympic tennis gold medals after they teamed for doubles titles in 1992 and 1996.