NEW YORK - Maria Sharapova advanced to a grudge-match US Open semi-final against top seed Victoria Azarenka while Serena Williams booked a last-four berth for the fourth time in five years in overwhelming fashion.

Russian third seed Sharapova reached the semi-finals for the first time since her 2006 US Open title run by rallying to defeat French 11th seed Marion Bartoli 3-6, 6-3, 6-4 in a match that began on Tuesday but was halted by rain.

Sharapova, who improved to 12-0 in three-set matches this year, faces a Friday showdown against World No. 1 Azarenka who beat Sharapova 6-3, 6-0 in last January's Australian Open final. "Tough challenge," Sharapova said. "She beat me in Australia quite easily and I would love to get my revenge at a Grand Slam."

Azarenka, who ousted defending champion Samantha Stosur of Australia on Tuesday, leads the all-time rivalry with Sharapova 5-4, including a victory in March's Indian Wells final and a loss in April's Stuttgart final on clay. "It's always tough to lose in that final stage of a Grand Slam," Sharapova said. "She has been playing great tennis. This is a great opportunity for the both of us."

US fourth seed Serena Williams, a 14-time Grand Slam champion seeking her fourth crown on the Flushing Meadows hardcourts, routed Serbian 12th seed Ana Ivanovic 6-1, 6-3 in 58 minutes, firing 12 aces in a commanding performance.

"I came out really strong," Williams said. "Playing someone like Ana, the former No. 1, I knew I had to come out strong and play some amazing tennis." Williams, who lost to Stosur in last year's final, will face Italian 10th seed Sara Errani on Friday for a berth in Saturday's final. "It's going to be a good matchup. She is such a fighter. She's so strong and quick," Williams said. "She has a great attitude. When you have such belief in yourself then you can do anything. I love her attitude. I'm inspired by it."

Williams has only dropped 16 games through five matches while blasting a tournament-best 41 aces. "I'm just so happy to be in the semis. It's so cool," Williams said. "I'm excited. I need this. I love to win and when I don't I'm really angry." Asked if she would would be shocked if Williams did not win the women's crown, Ivanovic replied, "Yeah, very."

Errani became the first Italian woman in the Open era to reach the US Open semi-finals with a 6-2, 6-4 victory over 20th-seeded compatriot, doubles partner and best friend Roberta Vinci. "It's always hard to play against a friend and it was strange seeing her on the other side of the net," said Errani. "I am happy to get to the semi-final. Can I win the title? I will tell you in three or four days."

Errani lost to Sharapova at this year's French Open final in her best career Grand Slam result. They could meet again for a trophy on the Flushing Meadows hardcourts if both can get past higher-seeded foes. "Serena is playing unbelievable," Errani said. "I'm in semi-final for something. I'm playing good. I have to play as well as I can so we will see."

First on Sharapova's mind is Azarenka. "We both play a pretty aggressive game, we're good competitors and we love to win," Sharapova said. "She has had such a solid year, her breakthrough in terms of winning the Grand Slam, being so solid, so consistent, being No. 1 in the world for the first time."

Sharapova, 25, improved to 5-0 all-time against Bartoli but only after falling behind 4-0 on Tuesday before rain halted the match, postponing the conclusion for a day and giving the Russian time to regroup. "I'm so happy to get through this one," Sharapova said. "It has been so long since I have been to this stage at the US Open."