Serena Williams opened her bid for the Olympic women's singles gold medal with victory over fellow former world number one Jelena Jankovic at Wimbledon.
Back on Centre Court, where she won her 14th Grand Slam title on 7 July, the American fourth seed beat her Serbian opponent 6-3 6-1 to make round two.
Kim Clijsters of Belgium, who is set to retire at the end of the season, overcame Italy's Roberta Vinci 6-1 6-4.
Roger Federer and all eight Britons are also in action on Saturday.