PARIS — For the third match in a row at the French Open, Serena Williams was oddly out of sorts at the outset and dropped the opening set.

And for the third match in a row, Williams righted herself to pull out a victory.

In a riveting, two-hour showdown between the last two American women in the draw, the No. 1-ranked and No. 1-seeded Williams was a game away from defeat Monday, then came back to beat Sloane Stephens 1-6, 7-5, 6-3.

Williams reached the quarterfinals and avoided joining defending champion Maria Sharapova on the way out of Roland Garros.

“It’s not how you start, I guess. It’s how you finish,” Williams said. “That’s kind of how I’m looking at it.”

Close as it was, thanks in large part to Williams’ 43 unforced errors, more than twice as many as Stephens’ 21, the eventual outcome seemed certain once Williams pulled even by taking the second set.

That’s because she is 10-0 in three-setters this season.

Williams is 29-1 overall in 2015 and owns an 18-match Grand Slam winning streak, including championships at the U.S. Open and Australian Open that gave her 19 major singles trophies.

The 1999 U.S. Open, when she collected her first major title, is the only other time Williams came back to win three straight matches after losing the first set, according to the WTA.