CINCINNATI, OH, USA -- Aryna Sabalenka of Belarus stunned No.13 seed Madison Keys of the United States and the Cincinnati crowd, dispatching the 2017 US Open finalist 6-3, 6-4, to advance to the Western & Southern Open semifinals on Friday night.

"Absolutely, that was a great experience for me, and I was so happy that I did it in two sets finally," Sabalenka said to the press, after the match. "I always enjoy to play on the center stadium, and there was a nice match. I'm so happy for that."

In the first Cincinnati quarterfinal showing for either player, the 20-year-old Belarusian put on a master class of power as she swept to another big win this week, having ousted Top 10 players Karolina Pliskova and Caroline Garcia earlier in the event, saving match points in each of those prior matches.

"You know, doesn't matter against whom you play," World No.34 Sabalenka said, regarding all her Top 20 wins of late. "I understand right now. It's just like, you have to come on the court and play and don't think about top players or this is not seeded players. Just, like, come and show people your best. It's enough."

Sabalenka had 19 winners to only 12 unforced errors, while Keys had 25 winners to 20 unforced errors during the high-quality encounter. But Keys failed to convert any of her 10 break points throughout the match, as Sabalenka was clutch in those instances. Sabalenka was 2-for-3 on break points to seal the win.

"I'm so happy I did it in two sets," Sabalenka continued. "Now I can, like, can be more calm, because before I was, like, 'Come on, just two sets, two sets, not three, please, please, please. You have to save your energy.'"

Sabalenka will face World No.1 Simona Halep in the semifinals. Halep picked up her second win of the day over Lesia Tsurenko in the quarterfinals, claiming 11 of the final 12 games of that match to reach the final four. In their only prior meeting, Halep defeated Sabalenka 6-2, 6-2, in the Shenzhen quarterfinals in the first week of this season.

"It will be a pretty tough match," said Sabalenka. "[Halep's] a great player, good fighter. It's going to be so tough for me, but I will do my best."

Sabalenka showed off her mettle by withstanding two break points at 2-2, eventually maneuvering her way through that game with a crucial hold. The steeliness paid dividends when she took advantage in the following game, breaking Keys for a 4-2 lead after the American punched an unforced error into the net.

Keys acquitted herself well for the remainder of the opening frame, using her power to hold onto her service and force Sabalenka to serve for the set at 5-3. But the Belarusian was totally unfazed by the occasion, reaching triple set point with a backhand winner, and claiming the one-set lead with a booming ace.

Sabalenka did not ease up as the second set commenced, crushing a backhand winner in the first game to set up break point, and converting it after a crosscourt backhand forced a netted error from Keys. The Belarusian then fought to consolidate the break, fending off three break points and miraculously holding for 2-0 with a second-service ace.

Keys continued to play top-tier tennis, but was never able to garner the break back in the second set. The American came close again when Sabalenka was serving at 4-3, holding two more break points. But both times, incredible serves by the 20-year-old bailed her out of trouble, and she resisted the urge to collapse as she held on for 5-3.

The final chance for Keys came on Sabalenka's serve at 5-4, as the Belarusian served for the match. A forehand winner by the American gave her a final break point, but Sabalenka, as was her custom, erased it with a brilliant serve -- this time, an ace. Two points later, another huge serve set up a forehand winner, and Sabalenka had pulled off another stunning win over a Top 20 player.