Returning this year from a 15-month maternity break, Osaka had fallen in the first round at the Australian Open in January but looked set to breeze into the second round in Paris as the former world number one bombarded Bronzetti from the baseline.

However, Osaka nearly imploded in the decider when she threw away a 4-0 lead before sealing victory in the two-hour contest to potentially play Iga Swiatek in the second round if the reigning champion beats French qualifier Leolia Jeanjean on Monday.

"I'm honestly really excited. I watched her (Swiatek) a lot when I was pregnant," Osaka told reporters.

"And honestly, I think it's an honour to play her in the French Open because she's won more than once here. It's a very big honour and challenge for me."

Osaka dominated the first set on a gusty Philippe Chatrier court to wrap it up in 28 minutes but her unforced errors rose steeply in the second, allowing Bronzetti to break in the crucial game at 5-4 and force a decider.

However, the Japanese player got back on track in the deciding set and had the opportunity to break for a 5-0 lead.

But she appeared to lose her grip on the tie as world number 67 Bronzetti clawed her way back into the contest, earning Osaka's applause on some winners while also frustrating the Japanese, who pounded the red dirt when the third set was tied at 4-4.

Osaka regained her composure and she pounced for a crucial break in the 11th game before finally clinching the back-and-forth battle.

"I was, in my head, thinking I didn't win a match in Australia so I'd really love to win one here. Obviously, that wasn't a good train of thought," Osaka said when describing her mental state during the match.

"Yeah, I kind of focused on it a bit too much instead of trying to play point by point. I think towards the end I was able to erase that thought from my head.

"But I would love to not have to go through that roller coaster again."