Serena Williams defeated Elena Vesnina 6-3, 6-1 to reach the second round of the Madrid Open on Monday.
The ninth-seeded Williams fired 13 aces and 40 winners during her opening match against Vesnina. Williams broke her Russian opponent four times during the first match at the Madrid tournament that is being played on the blue-clay court.
The ninth-ranked American will play Russia's Anastasia Pavlyuchenkova in the second round.
Williams' older sister Venus was to take on Angelique Kerber of Germany later Monday. Defending champion Petra Kvitova of the Czech Republic was to play Marina Erakovic of New Zealand.