NEW YORK -- When Emma Navarro played Coco Gauff a few months ago at Wimbledon, she was not yet a well-known quantity in global tennis. But then the 23-year-old American defeated Gauff in a straight-sets, fourth-round match.

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The irony? The All England Club was where Gauff first came to the attention of casual tennis fans when she reached the same stage as a 15-year-old.

All things considered, it was probably Navarro’s best match of the year -- and it brought a widespread recognition that she’s still wrestling with.

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“I think I’m on the radar,” Navarro told reporters here at the US Open. “In my own head I’ll probably always be under the radar just because I don’t give social media and that kind of stuff too much attention.

“I thought being on the radar would be more of a scary thing than it actually is. Now that I think I’m here, it’s not so bad.”

On Sunday at the US Open, the No.13-seeded Navarro backed up that breakthrough with a 6-3, 4-6, 6-3 win to advance to her second straight major quarterfinal. That ended No.3 Gauff’s title defense and a muscular 11-match winning streak in New York. And put Navarro, who began the year ranked No.31 on the PIF WTA Rankings, knocking on the door of a Top 10 debut.

"When I first left college, my coach and I kind of made like a two-year contract," Navarro said after the win, "that I would fully commit myself to playing professional tennis for two years and then kind of just reassess after that.

"I think I hit the two-year mark this June, and we didn't even acknowledge it or talk about it. So, yeah, definitely have surpassed my expectations for sure."

Gauff’s demise was largely self-inflicted. She was credited with 60 unforced errors and hit 19 double faults. And yet, until the final game she was very much in the match.

This was a bruising match. On many rallies, the two players blasted groundstrokes, using mostly the middle of the court. The first break of the match came with Gauff serving at 2-3. Back-to-back double faults, her fourth and fifth, gave Navarro some breathing room.

"I played really tough tennis," Navarro said. "It wasn't easy. I think both of us faced our own struggles at times. I think it was a little bit of a battle of will there for a bit. But yeah, proud of just my effort today."

After a second deuce, Navarro backed it up with a 105-mph ace down the middle and a backhand winner. Serving for the set at 5-3, she won the critical first point -- one that required 27 strokes -- and closed it out when Gauff’s service return found the net.

Ultimately, Gauff’s five double faults and 21 unforced errors were the difference.

A year ago, four of Gauff’s seven matches here went the three-set distance -- and three times she lost the first set. After dropping only five games in her first two matches this year, she lost the first set to Elina Svitolina in the third round.

After a bathroom break and some cold water to the face, Gauff came back and won in three sets.

“It was in my mind today,” Gauff said of the Svitolina match. “It gave me a lot of confidence just because it felt like déjà vu a little bit.”

Sure enough, Gauff found a way to reset and win the second set.

With Gauff serving at 3-all, Navarro forged her second break point of the frame. After running down Gauff’s nicely carved drop shot, Navarro flicked a gorgeous backhand winner down the line.

Gauff had three break points in next game and, when Navarro double-faulted, converted her first of the match. That made it 4-all.

With Navarro serving at 4-5, Gauff put together some terrific defense and broke her for the second straight time to send the match into a decider. After a mental result, Navarro showed why she's now an outstanding 19-8 in three-set matches this season. 

"I was able to stick in there through some tough moments," Navarro said. "Wasn't able to close out the second set, which was tough, but yeah, I was able to reset and come back out and meet a really similar moment in the third set a little bit better."

In the third game of the final set, Gauff came unstrung, throwing in three double faults (Nos. 10-12) in her last four points. That gave Navarro a 2-1 lead, but her mettle would once again be tested by Gauff down the stretch. 

The key point came with Navarro serving at 4-3, 0-15. In a point she had no right to win, Navarro out-scrambled Gauff in an all-court point that ended when Gauff drilled a forehand into the net. The younger American should have been up 0-30 with a chance to get back on serve. Instead, Navarro worked her way out of the game to keep the champion at bay. 

With Gauff serving to stay in it at 3-5, she stayed aggressive behind her serve but hit three doubles, and Navarro won when Gauff’s forehand sailed long and wide.

"Mentally I gave it and emotionally I gave it my all," Gauff said. "Of course, there were things execution-wise, where, obviously I wish I could serve better. I think if I would have did that, it would have been a different story for me in the match."

Navarro will face Washington D.C. champion and Paula Bodosa on Monday. The winner will advance to her first Grand Slam semifinal.