Serena Williams eased closer to a fourth US Open title on Monday, storming past Ana Ivanovic 6-3, 6-4 to set-up a quarterfinal clash with Anastasia Pavlyuchenkova, the youngest player left in the draw.
Williams, seeded a lowly 28 after a year spent battling injury and serious illness, has yet to drop a set at Flushing Meadows this year and former world number one Ivanovic never looked likely to break that streak.
The 29-year-old American raced into a 3-0 lead in the opening set on a windswept Arthur Ashe Stadium before 16th-seeded Ivanovic, who has never got beyond the last 16, hit back to level at 3-3.
But a break in the eighth game put Williams on course to take the opener.
Another break in the first game of the second set proved the foundation for victory which she secured when Ivanovic went long with a service return.
"It was so windy today, it was really tough," said Serena, who came into the US Open with titles in Stanford and Toronto, her first tournament wins after spending 11 months on the sidelines following Wimbledon in 2010.
"I feel so blessed to be back. A couple of months ago I never expected to be here. I feel so honoured now and every match is a bonus. It's all so exciting."
With defending champion Kim Clijsters not playing, and with former winner Maria Sharapova, Wimbledon victor Petra Kvitova and French Open titlist Li Na losing before the third round, Williams is comfortably the tournament favourite.
Russia's Pavlyuchenkova battled back to defeat seventh-seeded Italian Francesca Schiavone 5-7, 6-3, 6-4 to reach her first US Open quarter-final in a mistake-plagued last 16 clash.
Pavlyuchenkova, the 17th seed, triumphed in a match-up of the youngest and oldest players -- 20 and 31 -- left in the women's event.
But Monday's 2hr 42min match, which opened the programme on Labor Day, a national holiday in the US, was not for the purists with 21 double faults, 16 breaks of serve and a combined 95 unforced errors.
"It's a dream come true for me to reach the quarter-finals here for the first time. I'm so happy about it," said Pavlyuchenkova, who lost to Schiavone at the same stage last year and in the quarter-finals of this season's French Open.
At Roland Garros, she had squandered a 6-1, 4-1 lead before losing in three sets to Schiavone, the champion in Paris in 2010.
"It was much easier because it was a different situation," said the Russian, who was the 2006 junior champion in New York.
"There I was negative and tired, that's why I was 5-1 down in the third set very quickly. This time I won the second set, emotionally I felt better and I felt like I could win."
The 20-year-old needed three match points to secure victory after squandering two with a pair of ugly forehands before a booming forehand winner wrapped up the affair.
The day's other last 16 ties see top seed and world number one Caroline Wozniacki tackle 2004 champion Svetlana Kuznetsova, the Russian 15th seed.
Wozniacki, still without a Grand Slam title, was the runner-up to Clijsters at Flushing Meadows in 2009, beating Kuznetsova in the fourth round on her way to the final.
The Dane has a 4-2 winning record over the 26-year-old Kuznetsova. The winner of that tie will take on either German 10th seed Andrea Petkovic or unseeded Spaniard Carla Suarez Navarro.
Petkovic lost the pair's only other previous meeting at the 2010 Australian Open.
The German, who will be 24 on Friday, is bidding to reach her first US Open quarter-final having made the last eight at the Australian Open and at Roland Garros this year.
The remaining women's quarter-finals line-up was decided on Sunday with Vera Zvonareva, the second seeded Russian and runner-up last year, setting up a clash against Australian Samantha Stosur, the ninth seed.
Italian 26th seed Flavia Pennetta will be facing unseeded German Angelique Kerber in the other last eight tie.