Serena Williams continued her dominance at the U.S. Open on Wednesday night, dispatching Ana Ivanovic 6-1, 6-3.

The American used an overpowering serve and a vicious forehand to advance to the semifinals.

"I feel like I'm going to get more focused and serious and start playing Serena tennis in the next couple of rounds, if I get to play two rounds. That's my goal," Williams said to the Associated Press.

She had 12 aces in the match and was extremely successful on her first serve, winning the point on 26 of 29 attempts. Through five matches at the tournament, she has only lost 16 total games.

During the match, Ivanovic held her serve at 3-1 in the first set to snap a 23-game win streak for Williams.

''I think the quality of tennis compared to last year, it was much higher, I think from both of us,'' said Ivanovic to the Associated Press. ''I mean, she was serving unbelievable. She was hardly missing serves. That puts a lot of pressure on opponents' own service games.''

The only trouble for Williams came in the middle of the second set, where one of her service games played out over three deuces. Up 4-3, she won the game on two powerful winners that Ivanovic had no answer for.

Williams broke Ivanovic to go up 5-3 and closed out the match easily. Last year Williams beat Ivanovic, 6-3, 6-4 in the fourth round of the tournament.

Ivanovic hadn't made a quarterfinals appearance since the 2008 French Open.

Williams is a three-time U.S. Open champion and has been in top form for most of the year. She won at Wimbeldon for her 14th career Grand Slam and also was a gold medalist at the London Olympics over the summer.

In the semifinals Williams will take on Italian Sara Errani, who beat her doubles partner Roberta Vinci. The 10th-seeded player isn't known for her hard serve, but has had a consistent year, including an appearance in the French Open finals.

On the other side of the draw Maria Sharapova will take on Victoria Azarenka. Sharapova advanced after having her match against Marion Bartoli delayed on Tuesday.

She won 3-6, 6-3, 6-4 and has made it to the semi-finals at every Grand Slam this year except for Wimbeldon, where she fell in the fourth round. Sharapova won the French Open and made it to the finals of the Australian Open where she lost to Victoria Azarenka.