New York - Three-time champion Serena Williams stormed to a double bagel 6-0, 6-0 rout of Czech Andrea Hlavackova to reach her 10th US Open quarter-final on Monday in a ruthless display of her title credentials.
The 30-year-old American allowed the world number 82 just eight points on her serve and finished the last-16 clash with 31 winners against just seven unforced errors, backing up her 57-minute win with eight aces.
Williams, a 14-time Grand Slam title winner and the reigning Wimbledon and Olympic champion, has dropped just 12 games in four matches at the Open this year.
She hasn't lost a game in her last three sets played while Monday's mauling was the fifth time she had handed out a double bagel.
"Andrea played really well," Williams told the Arthur Ashe Stadium of her outclassed opponent, who departed the singles tournament $120,000 richer for making the fourth round of a Grand Slam for the first time.
"She never gave up. She's such a great fighter. But I played really well today, I tried to stay relaxed and do what I do. I knew she would be a dangerous opponent."
Williams has now reached a 34th quarter-final at a major and next faces 12th seed Ana Ivanovic.
The Serb reached her first Grand Slam quarter-final in four years - and first ever at the US Open - when she defeated Bulgaria's Tsvetana Pironkova 6-0, 6-4.
Ivanovic has never taken a set off Williams in her three defeats against the American. Two of those losses came at the US Open in 2006 and 2011.
The 24-year-old Ivanovic, whose last major quarter-final came on the way to her one and only Grand Slam triumph at the 2008 French Open, swept through the first set in just 23 minutes on Monday.
Pironkova, the world number 55 who became the first Bulgarian to make a Grand Slam semi-final when she charged into the last four at Wimbledon in 2010, was the first woman from her country to make the last 16 in New York since 1994.
But her challenge was restricted by a neck injury and she twice needed treatment, including a medical time-out at the end of the first set.
She battled gamely in the second set, breaking Ivanovic twice, including the ninth game when the former world number one was serving for the match.
But the Serb hit back immediately for victory in the 10th game with the match's 10th break of serve in the 16 games played.
"I hardly made any mistakes in the first set but she is a tough opponent and I knew she would come back in the second set," said Ivanovic after her 71-minute win, where she finished with 28 winners and 21 unforced errors.
"It's amazing to be in my first quarter-final at the US Open."
German sixth seed Angelique Kerber, a semi-finalist in 2011, faces Italian 10th seed Sara Errani, the French Open runner-up.
Errani defeated Kerber, who has a season-leading 56 wins in 2012, in the quarter-finals in Paris on her way to the final in June.
The winner of that tie will face either Polish second seed Agnieszka Radwanska, who has equalled her best performance in New York of runs to the last-16 in 2007 and 2008, or Italian 19th seed Roberta Vinci.
Radwanska has won all of her four previous meetings with the 29-year-old Vinci, who had made the last-16 for the first time.
Latest results from the US Open on Monday:
Tomas Berdych (6), Czech Republic, def. Nicolas Almagro (11), Spain, 7-6 (7/4), 6-4, 6-1.
Roger Federer (1), Switzerland, def. Mardy Fish (23), United States, walkover.
Ana Ivanovic (12), Serbia, def. Tsvetana Pironkova, Bulgaria, 6-0, 6-4.
Serena Williams (4), United States, def. Andrea Hlavackova, Czech Republic, 6-0, 6-0.
Sara Errani (10), Italy, def. Angelique Kerber (6), Germany, 7-6 (5), 6-3.