Paris, France, 1 June 2018 | AAP

Ash Barty’s brave bid to cut short Serena Williams’ Grand Slam comeback has ended in a tense three-set French Open defeat for the Australian No.1.

Barty appeared to be careering towards a famous victory before letting slip a one-set advantage in the 3-6 6-3 6-4 second-round loss in Paris.

Seemingly unfazed by the occasion, Barty broke the 23-times Grand Slam champion early in the second set to surge further ahead before Williams willed her way back into the enthralling contest on Court Philippe-Chatrier.

Barty’s game plan to move Williams from side to side in the hope of exhausting the underdone champion in just her sixth match back since giving birth last September initially paid dividends.

But the former world No.1 drew on her unrivalled fighting qualities – and energy reserves many doubted she still possessed at almost 37 and eight months into motherhood – to stave off Australia’s 17th seed after one hour and 46 minutes.

“It’s disappointing because I was well and truly in the match. And I felt off the baseline I was no issues at all,” Barty said.

“I would love to have five or six forehands again, a couple of those errors, and a couple more first serves, and I think it could be a different outcome.

“I feel like I wasn’t really doing too much wrong. I gave it a crack and it wasn’t enough.”

Williams admitted she didn’t know how she managed to turn the match around.

“I lost the first set and I thought I’ve got to try harder. I’ve got to just try harder and Serena came out,” she said with relief after setting up a third-round showdown with German 11th seed Julia Goerges.

Barty’s exit leaves former finalist Sam Stosur and 24th seed Daria Gavrilova to fly the Australian flag.

Stosur, runner-up at Roland Garros in 2010 and a semifinalist in 2009, 2012 and 2016, is through to the third round for the 10th straight year.

The veteran clay-court star plays 2016 champion Garbine Muguruza in a repeat of their semifinal two years ago after denying doubles partner Anastasia Pavlyuchenkova 6-2 7-6(1) earlier on Thursday.

READ MORE: Stosur, Gavrilova into third round

Gavrilova saved a match point in snatching a 5-7 7-5 6-3 victory from the jaws of defeat against American Bernarda Pera.

The great escape set up a return clash with Belgian 16th seed Elise Mertens, who eliminated Gavrilova from both last year’s French Open and the Australian Open in January.

Australian results on day five:

Women’s singles, second round
Serena Williams (USA) d [17] Ash Barty (AUS) 3-6 6-3 6-4
Sam Stosur (AUS) d [30] Anastasia Pavlyuchenkova (RUS) 6-2 7-6(1)
[24] Daria Gavrilova (AUS) d Bernarda Pera (USA) 5-7 7-5 6-3

Women’s doubles, first round
Nao Hibino (JPN)/Oksana Kalashnikova (GEO) d Daria Gavrilova (AUS)/Daria Kasatkina (RUS) 6-3 7-6(3)
[3] Andreja Klepac (SLO)/Maria Jose Martinez Sanchez (ESP) d Monique Adamczak (AUS)/Yafan Wang (CHN) 6-0 6-4

Men’s doubles, second round
[3] John Peers (AUS)/Henri Kontinen (FIN) d Mirza Basic (BIH)/Damir Dzumhur (BIH) 6-1 6-2