PARIS -- There was no doubt entering Thursday's semifinals that there would be an American woman advancing to the final of the French Open. The question was which dominant opponent would be waiting for her.
"She's No. 1 in the world for a reason," Stephens said of Halep. "I think that we'll just have to go out and compete. Somebody's going to win. Someone has to win. Someone has to lose. Just go out, give it your all, and whoever wins, wins."
The 10th-seeded Stephens had never made it past the fourth round in Paris until now. After sitting out nearly a year because of surgery on her right foot in January 2017, she has soared up the rankings and now made it to her second major final in the past nine months.
"Another great opportunity on Saturday, and I'm really looking forward to it," said Stephens, whose late father, John, was the 1988 NFL Offensive Rookie of the Year with the New England Patriots.
She improved to 3-0 against her longtime pal and Fed Cup teammate Keys, including their US Open final last September.
"It's never easy playing someone from your country, let alone someone you actually, like, care about and you're friends with," Stephens said. "It's very difficult. I think more when I do play Madi, it's just -- on the court it's very competitive. We are always very competitive. But it's a little weird. There's not as much, 'Come ons' and things like that."
Like Halep, Stephens is an incredibly talented defensive player, and she kept stretching points against a mistake-prone Keys, who made 41 unforced errors -- 30 more than Stephens.
Halep made quick work of Muguruza, the 2016 champion who entered the match having not lost a set to this point.
It will be Halep's second consecutive Grand Slam final and her fourth overall attempt to win her first title in a major. She lost the title match to Caroline Wozniacki at the Australian Open in January.
"I will try my best," Halep told the crowd at Court Philippe Chatrier, "and hopefully I will be better than last year.
"I'm happy that I can have another chance."
Halep assured herself of retaining the No. 1 ranking and reached her third final in Paris. She lost both of the previous ones in three sets, to Maria Sharapova in 2014 and to Jelena Ostapenko in 2017.
Muguruza, a two-time major champion who was coming off a lopsided victory against Sharapova, took quite a while to get going against Halep, who managed to keep sending ball after ball back over the net.
Backed by fans who loudly chanted her first name between games, Halep went ahead 3-0 in only 15 minutes with the help of only one winner. Of her first 14 points, 13 arrived via errors by Muguruza -- nine unforced, four forced.
It was 5-0 by the time Muguruza eventually claimed a game.
"It was very nice to play like that," Halep said. "I'm really happy that I could beat a player like Muguruza. She's a great opponent, a great player. And it's always tough against her. I think I played very well. ... I played again one of my best matches on clay."
The second set was more of a test for Halep, who was ahead by a set and 3-0 before falling apart against Ostapenko a year ago.
Muguruza's last stand came at 4-all in the second set, a 13-minute game in which she held three break points. But she failed to convert any of those, and Halep held there, before breaking at love to end it.
"She didn't miss a lot," said Muguruza, who could have claimed the No. 1 ranking had she won the title in Paris. "I think she gave very little free points. Her shots were very, very deep and very aggressive constantly. ... It is a very tough day, because, you know, it's one of those matches where you train so hard, you know, to achieve a Grand Slam final."
The Associated Press contributed to this report.