LONDON - As Serena Williams prepares for her 35th Grand Slam semifinal, the American star said a fear of failure is driving her bid for an eighth Wimbledon title.

Williams avoided a major upset on Tuesday as the former world No 1 battled back to beat Italy's unseeded Camila Giorgi 3-6, 6-3, 6-4 in a Centre Court thriller.

The 36-year-old's quarterfinal escape set up a last-four meeting with German 13th seed Julia Goerges on Thursday.

Serena hasn't won a Grand Slam since the birth of her daughter Olympia in September, and her last trophy came at the 2017 Australian Open.

"You're only as good as your last win, and it's been a while since I've won a championship," Williams said.

But the 23-time major winner is heavily favored to end her wait this week, fueled by the thought of reliving the painful sting left by her rare defeats.

"I hate losing. I mean, that's no secret. But I feel like every time I lose, I get better," she said.

"It's important for me to have the losses. Just the fewer the better for me!"

Williams is playing only her fourth tournament since becoming a mother for the first time.

Having shaken off the rust following her lengthy layoff after the complications with Olympia's birth, Serena is on the verge of a 10th Wimbledon final appearance and 30th in all four Slams.

"Everything right now is a little bit of a surprise, to be here, to be in the semifinals," she said.

"I always say I plan on it. But when it actually happens, it still is like 'Wow, this is really happening'."

With Olympia's arrival and her marriage to entrepreneur Alexis Ohanian both taking place since Serena was last at Wimbledon, this year's campaign has a unique feel.

"It's different now obviously because I have the baby. Being a mom is totally different," she said.

"I just want to be more of that role model for my daughter, for lots of people out there that just want to be inspired.

"Here is some good news. Right now there's so much bad news in the world. We just need a good story."

Having won the Wimbledon title in 2015 and 2016, Williams, who missed last year's tournament due to her pregnancy, has extended her winning streak at the All England Club to 19 matches.

In contrast, Goerges is in the semifinals here for the first time.

The 29-year-old dropped five straight Wimbledon first-round matches before this year.

It also took her until her 42nd Grand Slam appearance to finally get through to the last four of a major.

Yet Goerges insists she can cause a massive upset against Williams.

"It is a great opportunity to play Serena here where she has won so many times and is such a great champion," she said. "I think everyone here has a great chance so you have to take it."

Meanwhile, 11th-seeded German Angelique Kerber faces Latvia's 2017 French Open champion Jelena Ostapenko, who is seeded 12th, in the other semifinal.