LONDON, UK - Serena Williams is the "superhero" of the Wimbledon grass, according to Marion Bartoli, with the Frenchwoman also suggesting it is "scary" how well the new mother has played on the way to the semifinals. Bartoli's view is that the American is motivated by wanting to win for her daughter Olympia. 

At only her fourth tournament since returning from maternity leave, Williams is now just two matches away from an eighth Wimbledon title and equalling Margaret Court's all-time record of 24 majors.

"Serena's barely played any tennis and now she's come back and she is already playing at this level. But she's in another category, she's a superhero. She can turn up and win Grand Slams," the 2013 Wimbledon champion said of Williams, who plays Germany's Julia Goerges in Thursday's semi-finals. 

"I've been commentating on all Serena's matches and I think she's very close to her best level. She's maybe lacking a little bit of speed side to side, and maybe she's slightly less dominant with the return of service, but these are small things. To me, it's scary how close she is to being back to her best level."

Williams was pregnant when she won her 23rd major at the 2017 Australian Open. Less than a year after giving birth, she is closing in on another remarkable feat. 

"It's very difficult for me to say exactly what it's like for Serena because I haven't had a baby myself. But it's difficult enough to be away and to put your body back into the physical training. It's hard in the gym as you go back and your muscles are so sore. For so many days in a row, you're muscles are so sore that you're feeling as though you're going to die. The muscles are hurting everywhere," said Bartoli, who is competing in the legends event at the All England Club. 

But Williams has shown that she is willing to suffer, said Bartoli.

"I think Serena's mind is so focused and she is accepting that has to suffer. She is already a champion but she wants to prove it again and again. I don't know where she finds that desire and where it comes from, but it's definitely very present in her," she observed. "It's always been present in her, but it's almost like she wants to win for Olympia and to show her daughter that she can win. I think that's almost like her motivation."  

With Williams to turn 37 in September, there is much discussion about her future in the game.

"I saw Serena say the other day that she will retire when Roger Federer retires. Maybe they will retire on the same day, and then the whole of tennis will be sad and cry on that day," said Bartoli. 

Daniela Hantuchova, a former Wimbledon quarterfinalist, said Williams could potentially continue playing for several more years.

"I think Serena can play for as long as she wants to. She's such a great athlete and it's amazing that she still has the desire and the motivation to be out there," said the Slovakian, who is also playing in the legends event at Wimbledon. 

"The women's draw is so open this year. Of course, Serena has been among the favourites, but anything could happen. I've really liked what I've seen in her game. She's been playing well."