American Serena Williams hits a return to Victoria Azarenka of Belarus during their women's semifinal at the Wimbledon tennis championships in London.

London - Serena Williams produced another staggering display of power serving to reach her seventh Wimbledon singles final with a 6-3, 7-6 victory over Victoria Azarenka on Thursday.

The 30-year-old American, contesting a 21st grand slam semifinal, fired down a tournament record of 24 aces to snuff out the challenge of the second-seeded Belarusian who clung on bravely to force a second-set tiebreak.

Azarenka saved one match point at 5-6, but Williams blasted down another ace to seal it 8-6, moving to the brink of her 14th grand slam singles title and first since overcoming career-threatening injuries and illness.

She crouched down and started roaring with delight before shaking hands with her opponent and jumping up and down on Centre Court in scenes of unbridled joy.

“It definitely is quite special,” sixth-seeded Williams told a news conference. “I feel like just getting there and doing so well is pretty cool.

“I'm just trying to do the best that I can. I have so much appreciation for every moment on the court. I really take pride in playing in such amazing tournaments such as this.

Williams, who reached the doubles semifinals with her sister Venus later on Thursday, said she was not aware she was serving so well.

“I honestly didn't feel great on my serve today,” she said. “I thought my serve was off and clearly it wasn't.

“My game is pretty aggressive and I was just trying to play my game. My serve is mean and as I get older I rely on it a bit more.”

Williams dominated the first set in the sunshine, barely conceding a point on her own serve and regularly threatening to break Azarenka.

The second set was much tighter, however, as Azarenka clawed her way into the match, finding the range on her dipping groundstrokes and breaking the Williams serve for the first time in the sixth game.

The Australian Open winner pushed the four-times Wimbledon champion into a tiebreak and saved a match point when Williams lobbed long but the American took her next opportunity with yet another ace to seal victory in 96 minutes.

“I've been working so hard, I really wanted it,” Williams said.

“She was playing well and I got a little tight in the second set. I was looking too far in the future. I was just getting excited that I was so close, but I can't do that. I was happy to get through that second-set tiebreak.”

The American will play Polish third seed Agnieszka Radwanska in Saturday's final.

“My biggest challenge is Agnieszka is really, really good at everything,” Williams said. “She has unbelievable hands. She's running every ball down.

“It's going to be challenging. She's already ranked ahead of me, so I think it will be a really good match.” - Reuters