CINCINNATI: Ashleigh Barty kept her run at returning to the world number one ranking with a WTA Cincinnati Masters victory on Friday as one of her two last rivals for the spot fell out of contention.
The Australian top seed engineered her second comeback in as many days, overhauling Maria Sakkari 5-7, 6-2, 6-0.
Barty has a chance to top next week's rankings but current number one Naomi Osaka of Japan might also claim the spot.
Czech third seed Karolina Pliskova, who also had a chance at number one, fell to double Grand Slam champion Svetlana Kuznetsova of Russia 3-6, 7-6 (7/2), 6-3.
Osaka was playing for a semi-final berth later Friday against American Sofia Kenin.
Osaka, Halep advance while Barty beats Sharapova in Cincinnati
Kuznetsova, coming back in recent weeks from wrist problems which included surgery, was unable to play last month in Washington due to US visa problems.
She travelled to Toronto last week where she won a round and has accelerated even further here in the American Midwest flatlands.
Kuznetsova was treated several times on court for apparent hip and leg problems, with Pliskova looking out of energy at times during the two-and-a-quarter-hour struggle.
Pliskova had the match on her racquet, but was broken while serving at 5-4 in the second set.
Kuznetsova dominated a tiebreaker and took charge in the third set as Pliskova began to fade.
"It was simple. I tried to play every point and stay in there," Kuznetsova said. "She served amazing. She aced me almost every time I had a break point.
"I told myself to wait for the opportunities. I've been working hard with my team and I'm back with my former Spanish coaches. I'm fighting now to get every ball back."
World number one Barty bounced, Stephens falls in Toronto
Barty rallied from a set down in the previous round to defeat Anettt Kontaveit, but the reigning French Open champion is not stressing about the numbers, just concentrating on her steady tennis.
"I'm in the semis for the first time here," she said. "I'm not thinking of the ranking at all.
"I'm playing one match at a time. If I can win matches, the ranking will take care of itself.
"I've had an amazing three years with my team and an amazing season. I'm excited to be in new territory here in Cincinnati."
Top Greek player Sakkari came alive in the first set, battling from 5-2 down and winning 14 of the last 16 points to sweep the opener.
But Barty merely dug in to begin her fightback.
"I was more patient in the second and third sets. I served better, hit my spots," Barty said. "She was playing super-aggressive in the first set.
"I made a few simple adjustments, making her play a few more balls.
"I play my best tennis when my head is clear and I trust in my instincts. I can bring variety but get back to basics when I need to."
Barty defeated Sakkari with 29 winners and breaks on six of 14 chances over an hour and 45 minutes.
On the men's side, France's Richard Gasquet captured his first ATP Masters Series quarter-final victory in six years by defeating Roberto Bautista Agut 7-6 (7/2), 3-6, 6-2.
The 33-year-old Frenchman, who had lost seven consecutive ATP Masters quarter-finals since Miami in 2013, will play for a spot in the final against Belgian 16th seed David Goffin, who advanced by walkover against Japanese qualifier Yoshihito Nishioka, who could not take the court due to illness.