A shattered Serena Williams is in a desperate fight to be fit for Wimbledon after pulling out of the French Open with a pectoral muscle injury.

The 23-time grand slam champion withdrew just minutes before her scheduled blockbuster fourth-round encounter with career-long rival Maria Sharapova.

“Unfortunately it’s been getting worse to the point where right now I can’t actually serve,” Williams told a packed press conference in Paris.

“It’s kind of hard to play when I can’t physically serve.”

Making her grand slam comeback following the birth last September of her first child, the 36-year-old said she first felt the injury in her third-round win over Julia Goerges.

Before that, Williams had never experienced any such problem during her 20-year professional career.

“So I’m going to get an MRI tomorrow. I’m going to stay here and see some of the doctors here, see as many specialists as I can and I won’t know that until I get those results,” the American superstar said when asked if she still hoped to pursue an eighth Wimbledon crown next month.

“I’m beyond disappointed. You know, I gave up so much, from time with my daughter, to time with my family. I put everything on the court. All for this moment.

“So it’s really difficult to be in this situation, but I always, for now in my life, I just always try to think positive and just think of the bigger picture and hopefully the next events and the rest of the year.”

Serena Williams announces her withdrawal from #RG18 due to a right pectoral injury.

Wishing the three-time champion a speedy recovery. pic.twitter.com/bo3e1jkgcv

— Roland-Garros (@rolandgarros) June 4, 2018

Williams’s showdown with Sharapova had been billed as the most anticipated women’s match of the year.

The two grand slam giants hadn’t clashed since Williams beat Sharapova in the 2016 Australian Open quarter-finals, the day the Russian tested positive for Meldonium and was subsequently banned for 15 months.

Williams hasn’t lost to Sharapova since the 2004 Wimbledon final, winning their past 17 encounters, including the last 14 sets.

“It’s very difficult because I love playing Maria,” Williams added after being denied a chance to add to her three French Open crowns and possibly equal Margaret Court’s all-time record 24 grand slam singles titles in Paris.

“It’s just a match I always get up for. It’s just her game matches so well against mine.

“It is difficult because, like I keep saying, I have given up so much to be here.”

Sharapova’s walkover advances the dual French Open winner to a quarter-final on Tuesday against 2016 champion Garbine Muguruza, who advanced when unseeded Ukraine Lesia Tsurenko retired, also injured, while trailing the Spaniard 2-0 on Monday.

“I was looking forward to my match against Serena today and am disappointed that she had to withdraw,” Sharapova said.

“I wish her a speedy recovery and hope she returns to the tour soon.”

Williams said she had worked hard to get back in shape for her Grand Slam comeback, but was unable to serve as a result of the injury.

“Physically I’m doing great. It hasn’t been easy. I sacrificed so much to be at this event. I’m going to continue to get better. I had such a wonderful performance in my first grand slam back,” she added.

Monday’s match against rival Sharapova would have been their 22nd meeting, after both spent a year on the sidelines.

And while many considered the contest to be a grudge match of sorts, Williams said she didn’t “have any negative feelings towards her”.

"I've never had any hard feelings toward her."@SerenaWilliams shuts down rumors regarding @MariaSharapova.#RG18 pic.twitter.com/tMPeqiyoiY

— Tennis Channel (@TennisChannel) June 3, 2018

“I fell like negativity is taught and … women should bring each other up. A lot of people always assume that I feel a different way and that’s not true.

“If anything, I feel like we should encourage each other and the success of one female should be the inspiration to another.”

Serena thanked her fans for their support in an Instagram post on Monday, saying, “You always live to fight for another chance. I’ve done a lot of fighting and this is just the beginning. Thank you for the support. I love you.”

-with agencies