Defending champion Serena Williams put on a serving clinic Saturday, hitting 20 aces in a straight-sets win over Dominika Cibulkova that sets up a possible fourth-round matchup with former champion Maria Sharapova. The top-seeded American had at least two aces in each of her eight service games and overpowered the 46th-ranked Slovak 6-0, 7-5 in the day's first match on Centre Court. Williams won 37 of 43 service points and held at love five times. She won 19 of her first 20 service points, with Cibulkova putting only four returns in play in that stretch. http://sports.espn.go.com/sports/tennis/wimbledon10/news/story?id=5330793
