MASON, Ohio — Simona Halep moved within a victory of the No. 1 ranking.
The second-ranked Halep needed just 54 minutes to cruise past Sloane Stephens 6-2, 6-1 on Saturday in the Western & Southern Open semifinals, and can displace Karolina Pliskova as the top of the ranking with a victory over Garbine Muguruza on Sunday.
The fourth-ranked Muguruza reached her first W&S final with a 6-3, 6-2 victory over defending champion Pliskova.
The men's final will feature two first-timers. Grigor Dimitrov outlasted John Isner 7-6 (4), 7-6 (10) in the first men's semifinal. Nick Kyrgios beat David Ferrer 7-6 (3), 7-6 (4).
Halep, seeking her first No. 1 ranking, has yet to drop a set in the tournament and appears to be peaking at just the right time.
"I think I played my best match on hardcourt so far," said Halep, who can become the first Romanian woman to be ranked No. 1. "It felt great. I moved very well today. From the first point, I felt like I was going to play good tennis."
The final Sunday will be the first on American soil for Muguruza, who lost to Pliskova in last year's W&S semifinals after losing to Serena Williams in the 2015 finals. The Spaniard had lost six straight matches against Pliskova since winning their first in 2013.
"I was very precise with my shots," said Muguruza, who is 2-1 in her career against Halep, though the two haven't played since 2015. "I wanted to be more aggressive and take my shots. I felt pretty good out there — under control. Everything went my way."
Muguruza won when Pliskova sailed a forehand long on the fifth match point. Pliskova, who played part of one match and all of another Friday after rain forced postponements Thursday, had 28 unforced errors to Muguruza's 13.
Muguruza was coming off playing the tournament's longest match, a 2-hour, 45-minute three-set win over Svetlana Kuznetsova on Friday. That followed a 2-hour, 18-minute win over Madison Keys on Thursday, when she fought off three match points.
"I don't think I played my best tennis today," Pliskova said. "I think the energy was pretty low from my side. Obviously, a tough schedule for me the last two days - three matches in about not even 24 hours.
"I think she played very solid, not missing much and obviously serving well. Everything started, I think, in the first game of the first set."
Muguruza took charge early, breaking Pliskova in the first and last games of the first set.
She gained a second-set edge with a backhand winner on break point for a 4-2 lead before closing it out in 1 hour, 19 minutes.
Stephens, playing her fourth tournament since returning from January foot surgery, also was playing a third match in a span of 24 hours.
"That's never easy," she said. "I'm going to go with that. I didn't play that badly. She was a little fresher. It was just not a great day."
The 11th-ranked Dimitrov, who lost in the last year's semifinal to eventual champion Marin Cilic, had just one double fault and finished with nine unforced errors to No. 19 Isner's 28 in the 2-hour, 3-minute match. The Bulgarian will play the winner of the semifinal between Nick Kyrgios, who knocked out second-ranked Rafael Nadal in straight sets in a Friday quarterfinal, and David Ferrer.
"Today was, I think, one of those matches that I really had to just be patient," Dimitrov said. "I think that that was the key. I knew I'm not going to have that many rallies against John. I knew that he's going to serve big, bold serves. I just had to be very composed and use every opportunity that I had. I think in the end of the match, it was just a few points that made the biggest difference for me. I'm just happy obviously with the win, but I'm just happy with the way I kept myself together throughout the whole match. Just remained calm in those tough moments. I mean, I know it's nerve-wracking from outside, but it's even tougher when you're in there and have to receive a serve that comes 141 mph."
Dimitrov's composure was the key, according to Isner.
"The difference was he was a lot more decisive at the big moments," Isner said. "He was a little calmer as well — a little more free-flowing in big moments. I thought he played a high-level match. He certainly is in good form. I played well enough to beat a lot of players today — just not him."
The 23rd-ranked Kyrgios will be playing in his first ATP Masters 1000 final — the highest-level final of his career.
"Obviously, I'm excited, but it's just another tennis match to me," the Australian said. "I'll just go out and serve and whatever happens, happens. It'll be a tough match."
Kyrgios and Ferrer displayed remarkably efficient serving in their nightcap. They combined for six break points, converting none.
"He served really good," the 31st-ranked Ferrer said. "I didn't have chance in the second tiebreak. In important moments with the second serve, he played aggressive."