Every great fighter thinks they have one great fight left in them.

That old adage is usually applied to boxers who come out of retirement for another swing - but it feels particularly relevant as 44-year-old Serena Williams makes the next step in her comeback to professional tennis.

The 23-time Grand Slam champion will return to the singles court at Wimbledon next week after a four-year absence from the sport she once dominated.

In many eyes, the American superstar is the greatest player of all-time - certainly in the women's game - and she clearly believes she has the ability to win matches again.

But the reality is Williams has not played a competitive singles match since the 2022 US Open and launching her comeback at the All England Club is an ambitious move.

Williams insists she does not "need to win" and rightly says she has "nothing to prove".

The fire still burns in her belly, though.

"Serena's mindset has always been to be the best and not settle for mediocrity," former world number one Lindsay Davenport, one of Williams' main rivals in the early 2000s, told BBC Sport.

"I think we have to assume that she's coming back because she feels she's in a position where she can make an impact immediately in women's tennis."

It was only a matter of time before Williams would be tempted back to singles action after making her return on the doubles court at Queen's.

The US Open, which starts in late August, seemed a more obvious starting point.

But, having played two doubles matches and practised intensely at Wimbledon over the past few days, Williams believes she is sharp and solid enough to return at the place where she won seven singles title.

A lot of athletes dream of rolling back the years but discover the reality of proving they can still compete - and not simply indulging in a nostalgia trip - is a different matter.

Williams, who turns 45 in September, is the oldest player in the women's singles main draw by some margin - she has six years on Germany's Tatjana Maria, the oldest player in the WTA top 100.

Williams is an inspiration to millions across the world and her message of being able to "do anything at any age" is admirable.

But there is no doubt that age is likely to be a barrier to her hopes of winning singles matches at Wimbledon, and two doubles matches does not feel like enough preparation to beat the world's very best.

There is little comparison between singles and doubles in terms of athletic output. Williams' movement and stamina will come under severe examination by her more youthful opponents.

The majority of the leading women's players are around 20 years younger than Williams, including 28-year-old world number one Aryna Sabalenka and reigning Wimbledon champion Iga Swiatek, who is 25.

"It doesn't get easy as you get older and grass is a tough surface to start on," Davenport said.

"The ball goes very quick, very low and it's very physical - there is a lot of bending.

"It's not going to be easy [but] if anyone could do it, certainly it could be her."

Former world number one Kim Clijsters found out how hard a comeback is when she returned aged 36 in 2020, unable to win any of her five matches over the next 18 months.

Three-time Grand Slam champion Angelique Kerber fared better in her 2024 comeback, but lost in the first round in all three of her major appearances.

"It's easier to see on TV how the girls are playing and say 'OK I can still do it'," Kerber, who came back aged 36 after having a baby, told BBC Sport.

"You know you can do it - especially Serena because she was the greatest.

"But working every day, going to the practice courts, going to the gym, sweating, is what you have to do."

Williams has not won a Grand Slam since the 2017 Australian Open, when she was 35. She has since given birth to two daughters - Olympia, now aged eight, and two-year-old Adira.

After her first comeback in 2018, Williams reached four Grand Slam finals - twice at Wimbledon and twice at the US Open - but lost them all.

Her past two Wimbledon appearances - in 2021 and 2022 - have ended in first-round defeats.

What Williams has in her favour is one of the greatest technical talents ever seen - and an incomparable aura.

Winning a 24th major to tie Margaret Court's all-time women's record seems out of reach, but Williams will have looked at the open nature of the WTA Tour and felt there are plenty of players she can still beat.

The power and accuracy of her serve was particularly effective on the grass and she will be hoping her opening shot can earn her plenty of free points.

Her odds of winning matches are certainly favourable at Wimbledon, especially if she faces a relatively inexperienced opponent who may get overawed by what is bound to be an electric occasion on Centre Court.

World number nine Victoria Mboko played doubles with Williams at Queen's and was convinced the veteran is "ready to go".

"She has such clean ball striking. She could take years off and once she steps on the court she could probably find her rhythm and timing again," said the 19-year-old Canadian.

"I think that's really a god-given gift she has. I'm hitting with her and she's hitting pretty big."

In her pomp, Williams was the embodiment of fitness and athleticism.

Last year, she admitted she had used weight loss drugs in order to lift what she called the "stigma" around using such medication.

Williams said she had struggled to lose weight she had gained during pregnancy - a common experience for many women - and returns to tennis looking lean.

"We've all seen her. She looks in incredible shape and better shape than arguably when she left the sport," Davenport said.

"But we have got to be a little graceful in the time we give her until she hits her peak."

Williams might not get anywhere near her best and she doesn't know how long this comeback will last.

But one thing is certain: the woman who many consider to be the GOAT will go down swinging in pursuit of restoring former glory.