American Coco Vandeweghe, who disposed of Sam Stosur in the third round, complained to the umpire about Sharapova moving during her serve motion in her three-set loss to the Russian.

"She was moving around in the middle of my motion on my second serve," Vandeweghe said about the No.4 seed.

"That's why I spoke to the umpire. She said she didn't believe she was doing it during the motion. I strongly disagreed. Towards the later end of the second set, I said if she has a problem speaking to Maria, if she's too scared to do it, I had no problem speaking to her.

"What I experienced, what I felt from her moving around in between my serving motion was not, I don't think, sportsmanlike, in my opinion. I try to play as fair as I can. You know, when I felt like it wasn't being reciprocated, that's when I spoke with the umpire for her to deal with.

Sharapova, who progressed following a 6-3, 6-7, 6-2 victory, was unaware of the 23-year-old's gripe when asked in the press conference, refusing to react to her opponent's accusations.

"I mean, it is what it is," Sharapova said.

"What she said, I'm not going to argue against her words."

On the other side of the draw, Poland's Agnieszka Radwanska overcame American Madison Keys (7-6, 3-6, 6-3) in three sets

The No.13 seed will now take on Garbine Muguruza, who defeated Timea Bacsinszky in straight sets (7-5, 6-3) to become the first female Spanish player to reach the semi finals at Wimbledon since Arantxa Sanchez Vicario in 1997.

Sharapova's victory has set up semi-final showdown against Williams, who the Russian hasn't beaten in 11 years.

One of Sharapova's two wins from 19 matches against Williams, who defeated Victoria Azarenka 3‑6, 6‑2, 6‑3 on Tuesday, came at Wimbledon in 2004 when she demolished the American to win the final in straight sets.

"Definitely no secrets between each other's games," Sharapova said.

"I haven't played Serena here in 11 years. That would be an incredible moment for me to step out on centre court against her again ...  I think it's always a new match. I haven't had great success against her. I would love to change that around. That's how I look at it."

Sharapova is a five-time grand slam winner and ahead of her match against Williams, she took the time to reflect on her only Wimbledon triumph more than a decade ago.

"Well, I haven't seen the name on the trophy in a while 'cause I haven't held the trophy in many years," Sharapova said.

"I've seen it on the board. I know it's there, but I would love to check it out again to make sure it's still there. That would be nice. Look, obviously being a small part of its history is an incredible feeling. It's something that I'll be able to cherish for the rest of my life. Be able to tell my future children that mummy won Wimbledon. I have proof. It's on the trophy.

"It's an incredible achievement. As you go about your career, you don't always realise your accomplishments because we're so busy and always thinking about the next one, the next event, trying to do something better and keep going, that you never have the time to slow down and really appreciate all your accomplishments, even as a young teenager girl. So I think I'll really be able to hopefully share those memories with my kids when I'm older."