Three-time U.S. Open champion Serena Williams won by a 6-0, 6-0 score for the first time in 62 career victories at Flushing Meadows.
Williams routed 82nd-ranked Andrea Hlavackova in 57 minutes Monday in the fourth round. The 14-time Grand Slam champion had 31 winners and just seven unforced errors.
Hlavackova, a 2011 French Open doubles champion, had never been past the second round in singles at a major tournament before this year.
Williams next faces 12th-seeded Ana Ivanovic.