Serena Williams narrowly escaped a spirited performance from No.7 seed Aryna Sabalenka on Sunday with a 6-4, 2-6, 6-4 win to reach the Australian Open quarterfinals.

In an anticipated first meeting between them, it was the 10th-seeded Williams who advanced in two hours and nine minutes, denying Sabalenka the first Grand Slam quarterfinal showing of her career.

"It was obviously real important because I didn't want to be out of the tournament, so it felt good to kind of clutch that in the end and get through that," Williams said during her post-match press conference.

The former World No.1 Williams quests for an eighth Australian Open title and record-tying 24th Grand Slam title continue. She fired 30 winners, including nine aces, to hand Sabalenka only her second loss in her past 20 matches. 

Williams moved on to the Australian Open quarterfinals for the 13th time. 

"I just felt like even games that I lost, I was so close to winning," Williams said. "Not all games, but probably most of those games. I just needed to play better on the big points. I knew that I could. I still hadn't reached my peak. I was like, 'Okay, Serena, you got this, just keep going.'"

She's really one of the only voices I hear. I don't know if I zone out and she's the only one I hear. I know when I hear her voice, it just makes me calm and confident. Yeah, I think there's something about it that just makes me feel really good.

- Serena Williams, on having her sister Venus support her in the crowd

Williams will now face two-time Grand Slam champion Simona Halep, who beat reigning French Open champion Iga Swiatek in three sets late Sunday night in Melbourne. 

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In the first set, Sabalenka had two break points at 3-3, but Williams cracked multiple service winners to escape.  She then used a mix of power and defense to grit out the first break of the match in the last game of the opener.

Williams could not keep the momentum in the second set. Her first-service percentage dipped to 36 percent and Sabalenka broke the American’s first three service games. It was the first set Williams lost this tournament. 

Williams raced to a 4-1 lead in the decider before more strong groundstrokes from Sabalenka pulled her back on serve at 4-3. Undaunted, Williams swept four points in a row to hold for 5-4 and put the pressure on Sabalenka to stay in the match. A double fault and two forehand errors were Sabalenka’s undoing. Williams clinched the decisive break to grab victory.

"I think it's great depth again," said Williams, surveying the field. "I think it's been a lot of players that really could win the title since the beginning of the draw. I think there's so many players that can come out and have won Grand Slams and can keep winning.

"It's good. It's good to see. It's good to see that I'm in that mix, too."

Stat check: Williams's seven Australian Open titles (2003, 2005, 2007, 2009-2010, 2015, and 2017) is a record in the Open Era (since 1968). Her 20 appearances at the Australian Open ranks second among active players, behind her sister, Venus, who has made 21 appearances.