NEW YORK — Venus Williams isn't having any trouble advancing at the U.S. Open, unlike many of the other top women's seeds.

The Wimbledon champ beat No. 27 seed Alona Bondarenko of Ukraine 6-2, 6-1 on Saturday to move on to the fourth round. The seventh-seeded Williams has dropped just 11 games in three straight-set wins.

"I think that definitely the Wimbledon win helped me a lot to change my mentality, to realize not every thing has to be perfect all the time," Williams said. "That's helped me to, if I don't have a perfect practice, I don't get really upset about the whole tournament."

Four of the top 10 women's seeds have lost, including No. 1 Ana Ivanovic. Williams and sister Serena are the only two former champs still alive.

Serena was set to play later Saturday. A win, and the sisters would be one victory away from a quarterfinal matchup.

No. 1 seed Rafael Nadal came back from down a break in the second set to beat Viktor Troicki of Serbia 6-4, 6-3, 6-0. His next opponent will be American Sam Querrey, who reached the fourth round of a grand slam for the first time with a 7-6 (5), 7-6 (5), 6-2 victory over No. 14 seed Ivo Karlovic of Croatia.

The 20-year-old Querrey came into the year with two goals: to win an ATP tournament and to raise his ranking into the 30s.

He has accomplished both, winning in Las Vegas in March and climbing to No. 38 in May. Currently ranked 55th, his next goal is to end the year at No. 32 or better so he'll be seeded at the Australian Open.

The 6-foot-6 Querrey is considered the tall guy with the big serve against most opponents, but not the 6-10 Karlovic. In his second-round match, Karlovic led Florent Serra in the aces department 42-0.

This time, Karlovic only edged Querrey 24-20 and struggled to win points against Querrey's serve. Karlovic managed just three break points and didn't convert any.

"If I can get my racket on the ball, it's not too bad," Querrey said of Karlovic's serve. "I'm a tall guy, as well. It's up near my shoulders, where other guys it's toward their head. ... Against a guy like him, there's a sense of urgency to every point, especially when he's serving."

Julie Coin's magical stay at the Open is over. The world's 188th-ranked player upset Ivanovic on Thursday, but her run ended in the third round with a 6-4, 6-4 loss to fellow Frenchwoman Amelie Mauresmo, the No. 32 seed.

Williams will next face No. 9 seed Agnieszka Radwanska of Poland. Radwanska beat 18th-seeded Dominika Cibulkova of Slovakia 6-0, 6-3.

Radwanska defeated Williams in their lone meeting, a straight sets victory in Luxembourg in 2006 when Williams was battling a wrist injury.

Williams came into the net 10 times against Bondarenko and won the point on nine of them. She said she's trying to come in whenever she has the chance, because "that's what I've been taught my whole life."

Except she didn't always do that.

"I was younger, and I didn't listen that well," she said with a laugh. "It was tough. But I'd like to think now that I'm wiser. I'm ready to listen to my coach."