NEW YORK -- Every step Coco Gauff takes these days, it seems, creates another milestone.

On Sunday, for example, she defeated 33-year-old wildcard Caroline Wozniacki 6-3, 3-6, 6-1 to become the first American teenager to reach back-to-back quarterfinals at the US Open since … Serena Williams.

Take a look at the other players on that list -- Venus Williams, Andrea Jaeger, Tracy Austin and Chris Evert -- and you can see why this 19-year-old has the tennis world so excited.

US Open 2023: Draw | Order of play | Scores | 411

On Tuesday, Gauff will play No.20 Jelena Ostapenko, the woman who knocked her out of the Australian Open in January. 

“Caroline’s back -- it’s like she’s never left,” Gauff said in her on-court interview. “She’s been an inspiration growing up. She definitely gets to a lot of balls. Sometimes I felt like I was playing myself.

“I knew I had to be aggressive today. In some moments I missed, but I was happy I was able to get back and focus.”

Gauff stroked 33 winners, overcoming 44 unforced errors.

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This was an intriguing, first-time matchup, featuring the youngest and the second-oldest players left in the women’s draw; Romania's Sorana Cirstea, who booked her spot in the quarterfinals earlier, is nearly 100 days older than Wozniacki. There was a sweet symmetry to it, for Gauff became the most recent teenager since Wozniacki to collect her fifth WTA Tour title, which she did two weeks ago. When Wozniacki made her Tour-level debut in Cincinnati in 2005, Gauff was just past her first birthday.

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The No.6-seeded Gauff and Wozniacki are universally beloved and the crowd at Arthur Ashe Stadium (including director Spike Lee) wasn’t afraid to cheer for them both. Gauff was the favorite; since losing her first-round match at Wimbledon, she has now won 15 of 16 matches and the two biggest titles of her young career.

Defense, it seemed certain, would dominate, although Gauff possessed significantly more firepower. Increasingly, she seems willing to use it.
 
Wozniacki won the first game on Gauff’s serve when the American donated four unforced errors. Aided by a double fault, Gauff got it back for 2-all and took control from there. With Wozniacki serving down 4-3, Gauff turned up the heat and, jumping on a second serve, hit a backhand winner to give her three break points. She only needed one, when Wozniacki’s forehand flew long.
  
Wozniacki had a sniff in the second set, as she increased the pressure on Gauff's service games. The American found ways to save break points to escape, but the respite didn’t last long. With Gauff's forehand breaking down under pressure, Wozniacki played an aggressive, all-around game to take a 5-3 lead that held up.
 
The players exchanged nervous breaks to open the third set. But Gauff found herself up 3-1, serving for 4-1, when two tentative Wozniacki backhands found the net. Wozniacki grabbed a quick break point when Gauff double-faulted, but some superb defense saved her.
 
After building an insurmountable 5-1 lead, Gauff closed out the win emphatically after two hours of play.