Officials have already postponed the start of play on Wednesday by at least an hour, amid fears the whole day might be wiped out because of the grim weather forecast in Paris.
Eighth-seeded Barty had been set to open proceedings on Court Suzanne-Lenglen, having carved her way through to the last eight at the clay-court major for the first time.
Gabriela Sabatini is the latest tennis great to jump on the Barty bandwagon as the Queenslander chases Roland Garros redemption and a spot in the semi-finals.
Rod Laver has already said Barty "can go all the way" and win her maiden major on Saturday, while three-time champion Arantxa Sanchez Vicario has declared the world No.8 is the most-feared player in the draw because of the "amazing variety" in her game.
Now it seems Barty has caught Sabatini's eye during her stellar breakout season.
"I like Barty, the Australian player. I like her very much," the former US Open champion said.
"I saw her (win) in Miami. I really like the way she plays - her slice, backhand slice, I like very much. She's a very strategic player."
But to continue her quest to become Australia's first singles champion in Paris since Margaret Court in 1973, Barty must reverse a 6-3 6-2 first-round hammering at the hands of Keys two years ago - in a match she would love to forget.
Barty is a vastly different player now, as evidenced by her straight-sets win over Keys during her unbeaten run this year in Fed Cup.
"So I think it's very much a fresh, clean slate from this match (like it was) at Fed Cup that we had as well," she said.
"Different surface. I mean, as different as you can probably get, indoor hard to an outdoor clay court."
After taking out Serena Williams' third-round slayer in her last match, Barty can repeat her Fed Cup double of the two Americans in back-to-back encounters, having beaten Sofia Kenin and Keys on successive days in February.
Victory over last year's semi-finalist and 2017 US Open runner-up Keys would also continue Barty's steady progression at the slams.
Barty has advanced one round better at each of the past three majors, following up a third-round effort at Wimbledon last year with a first-time foray to the last 16 in New York and then charging into the Australian Open quarter-finals in January.
"She's obviously had really good success here in the past," Barty said.
"It's an amazing opportunity for me to go out there and try and play my brand of tennis again, and take it to her as much as I can."