"There is a lot of times where I feel like she made the ball by a centimetre", Keys continued, "and I was missing it".
But the 26-year-old Romanian battled back to take a see-saw second set against the US Open champion.
Like Halep, Stephens is an incredibly talented defensive player, and she kept stretching points Thursday until Keys would err.
Stephens has been so impressive in Paris, dropping just one set on the way to the final, that it's hard to believe she went through a horror run of results not too long ago. In the 2014 final, she also lost in three sets to Maria Sharapova. And I have two more days until I will play the final.
No. 13 seed Madison Keys and 14th seed Daria Kasatkina are the toughest opponents Stephens has faced at Roland-Garros this year, while Halep's two most recent wins, against Angelique Kerber and Muguruza, prove her credentials more. Halep hopes to make her fourth career grand slam final and her third career French Open final. "Like I said, you have to just take your opportunities when you get them, and it's just match by match, basically". I don't think you have to be mean in order to win matches.
"I thought it was really fearless and she was sort of making a statement too".More news: Kitty Hawk takes pre-orders for Flyer personal aircraft
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Many Americans struggle on the red dirt because of the lack of red clay courts in the United States but several players have managed to master the surface nonetheless. She made decent inroads in the tournament that turned her away previous year but clearly viewed it as incremental progress after a flat, straight-sets loss to Spain's ascendant Garbine Muguruza. The other was an eight-match losing streak that began right after she won her first major trophy at last year's U.S. Open and included a first-round exit at this year's Australian Open.
About 12 hours after announcing her first sponsor, Katie Ledecky was back in the pool, doing what she does best - swimming fast times. Whereas Halep has an unenviable record at the sharp end of majors.
Stephens continued to dominate and broke in the first and seventh games of the second set to put herself in a position to serve for the match.
Keys made it to the semis with a straight-sets win over Kazakhstan's Yulia Putintseva while reigning US Open champion Stephens eased past Russia's Daria Kasatkina. "Then I changed a little bit of tactics and it worked".
Muguruza has not dropped a set in this year's tournament and dominated Sharapova with booming groundstrokes and superb returning that earned six breaks.
When asked June 3 about the remarks ahead of bowing out of the French Open because of an injury, Williams said she was surprised that so much of the book was about her.