NEW YORK - Because of a sprained left kneecap, Venus Williams took a lot more time off before the U.S. Open than originally planned.

Those two months away from competition sure haven't presented any problems so far.

Her play sparkling as much as her sequined dress, Williams easily eliminated 185th-ranked qualifier Mandy Minella of Luxembourg 6-2, 6-1 on Friday night to reach the U.S. Open's fourth round for the 12th time in 12 trips to the tournament.

She said she's had "really no thought at all" about shaking off rust.

"My whole thing was to try to bank on my experience, which so far is working," the No. 3-seeded Williams said. "My concern is always to be able to make the play and to play the level that I'm used to."

Former No. 1 Ana Ivanovic is back in the fourth round of the U.S. Open for the first time since 2007, and she'll take on defending champion Kim Clijsters next.

Ivanovic easily eliminated 157th-ranked wild card Virginie Razzano 7-5, 6-0 in the third round.

Williams' resume includes seven Grand Slam singles titles, including at the U.S. Open in 2000 and 2001. She also was the runner-up in New York in 1997 and 2002.

After losing in the Wimbledon quarterfinals June 29, the American was supposed to return to the tour on the hard-court circuit in early August at Cincinnati, then play at Montreal. But she hurt her knee shortly before Cincinnati, and came to New York without any match preparation.

How's that working out?

Williams has dropped a combined 17 games through three rounds.

Against Minella, she won the point on 18 of 21 trips to the net, helping her build a 29-5 edge in total winners.

"Really just concentrating on the footwork and moving forward," Williams said. "I think without the moving forward, I could have been involved in a lot of long points."

She wore her third outfit of this year's tournament, all self-designed — although nothing as attention-grabbing as her black, lace dress at the French Open.

"This outfit was really about New York. ... It's like bursts of fireworks," Williams explained. "It's about a celebration of me playing my best obviously at home and kind of doing what I love and being able to wear something fun while I do it. So just always trying to do something fun on the court."

Her younger sister Serena, who withdrew from the tournament because of a foot injury, watched the match in the stands.

Slideshow   Return to New York Take a look at all of the action from the 2010 U.S. Open. NBCSports.com

"It was good to see her tonight," Venus Williams said. "Usually we're at the tournament together. This year is an exception, but always good to have her back."

Minella entered this U.S. Open with an 0-5 career record against opponents ranked in the top 50, but knocked off No. 34 Tsvetana Pironkova and No. 47 Polona Hercog to set up a matchup against the older Williams.

After the match, Williams was honest, saying: "I had no idea what my opponent played like."

Minella's serve was broken in the match's opening game — and each of the next five times she served, too. When Minella finally held serve to trail 4-1 in the second set after a 20-point game that included four break points, she waved her arms overhead to the crowd in mock celebration.

Williams is the only woman this season to reach at least the fourth round at all four Grand Slam tournaments. Top-seeded Caroline Wozniacki can match that when she plays her third-round U.S. Open match Saturday.

In the fourth round, Williams will meet 16th-seeded Shahar Peer of Israel, who beat No. 19 Flavia Pennetta of Italy 6-4, 6-4.

"I know she has the talent to do something big. She already has in her career," Williams said about Peer. "I want to just get out there and execute my game to the point where I get to that next round."