NEW YORK, NY, USA - Aryna Sabalenka extended her winning streak to eight matches in a row after stunning the No.5 seed Petra Kvitova 7-5, 6-1 under the lights at Louis Armstrong Stadium.

Sabalenka, who lifted her first WTA trophy last week in New Haven, came into her first US Open main draw sitting at a career-high ranking of World No.20 and seeded at a Grand Slam for the first time.

Read more: Sabalenka finds 'calm' on court to claim New Haven crown

She’s shown no signs of slowing down, firing 21 winners across two sets to storm into the fourth round at the US Open - her best Grand Slam result to date.

“I'm just so happy with my game at the moment,” Sabalenka told press afterward. “Actually, before every match, I'm a little bit nervous. But when I come on the court, I see these people that support me, let's say. I enjoy it. I enjoy the game. I didn't have any pressure. Well, I'm just playing every point.”

The 20-year-old Belarusian had Kvitova under pressure from the start, creating two break chances on the Czech’s first service game and then grabbing the first break a few games later to lead 2-1. Sabalenka had points to extend her lead to a double break, but Kvitova came roaring back, stepping into her shots and leveling the score at 3-3.

The pair traded breaks twice, with Sabalenka having to fight her way back into it both times as Kvitova broke to level the set at 3-3 and later again at 5-5. Sabalenka’s relentless attacking of Kvitova’s second serve finally rewarded her with the decisive break at 6-5, and the New Haven champion comfortably served it out to love.

"I had my chances in the first set - and I took it, but I lost it again and then she took it all the way," said Kvitova ruefully afterwards. "She was really playing aggressive, and I didn't have the answer for that when she put those winners over there." The former World No.2 acknowledged that she struggled on serve, too - "I think if I don't make that many double faults, it would be a bit different," she said.

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With Sabalenka dialed in and blasting winners off both wings, the second set was a decidedly one-sided affair as she reeled off the last six games in a row to seal her spot into the second week of the US Open.

Up next, Sabalenka will face another big hitter as she takes on No.20 seed Naomi Osaka in her next match.

“I didn't think about it, I didn't play against her before,” Sabalenka said. “I know she's quite aggressive player. She put a lot of balls in, quite hard. Well, I don't know, we will think about it with the coach.”

For Kvitova's part, the five-time WTA titlist in 2018 is left to regret a disappointing season at the Slams compared to other tournaments. "[At the] Australian Open and Wimbledon, it was a similar thing - I was a bit passive and I didn't have the confidence I needed to play, and I put a lot of pressure on myself," she recalled. "I really tried to change it for this Grand Slam - I definitely felt the best here, and I had a great two rounds. Hopefully I find a way, but every day is different."