Cocomania may be done at the U.S. Open. But McCoco is alive and well.

Coco Gauff’s stunning singles run ended in tears with Saturday’s much-hyped loss to world-No. 1 Naomi Osaka. But the 15-year-old American phenom was all smiles and giggles while partnering with Caty McNally to reach the third round of women’s doubles.

Gauff and McNally earned a 6-3, 7-6 (9) second-round win over Nicole Melichar and Kveta Peschke at a packed Louis Armstrong Stadium on Sunday.

“I came into both matches with the same mentality,” Gauff said. “I just think the difference between [the two] is that [Sunday] we won and [Saturday] I lost.”

It was an entirely different vibe in the laugh-filled aftermath, where — despite a pre-match lesson in who Armstrong was — Gauff thought his nickname was Saxamo (it’s Satchmo), and McNally thought he played the saxophone (he plays the trumpet). It’s a reminder that they’re 32 years old — combined.

The duo still hasn’t dropped a set since teaming up, staving off seven set points in their first set at the U.S. Open to their tiebreaker victory, a win they celebrated with a Bryan Brothers-style bump.

So-called McCoco moved on to play Victoria Azarenka and Ashleigh Barty.

Meanwhile, age restrictions will likely keep Gauff from playing singles again until the Australian Open, according to her father, Corey.

“Long term I learned a lot from these couple weeks,” Gauff said. “I’m going to use what I’ve learned the past [few] matches in my next couple tournaments.”

Those lessons will prove invaluable. Some of that advice even came at last year’s U.S Open from Osaka’s father, Leonard Francois.

“Last year [Francois] said, ‘Why are you still playing in juniors? You need to move up to a higher level.’ That was good advice,” Corey said.

Clearly. Gauff burst onto the world scene at Wimbledon, setting the stage for Cocomania to rule the U.S. Open. But she learned lessons even in that defeat, when Osaka painted the lines and kept her out of sync, while her own serve struggled.

“You learn from it. It’s a great experience. A lot of people would love to have a chance to play three matches at the U.S. Open. … We have a pretty significant break to work on her game after the Open. Hopefully we improve in a lot of areas and next time she executes in those,” Corey said.

“A lot can happen in a year. Last year I was preparing for juniors,” Gauff said. “Now I almost got to the second week in my first main-draw U.S. Open. I’m super-proud of myself. I’m just going to continue to learn. My dad told me I’m 15, I still have a lot to work on, a lot to improve.”

That fact wasn’t lost on those who watched her up close, from USTA GM of Player Development Martin Blackman (“It’s her poise — handling moment after moment against really good players. It’s problem-solving, dealing with everything that comes along with 15-year-olds. That was really impressive.”) to Roger Federer.

“It’s incredible at 15. I can’t even think being so well-behaved at 15,” Federer said. “Just the way she handles pressure being out on the court, we forget it’s not routine to be in front of 20,000 [fans] and facing the pressure. … [At 15] my game was not even close. I would’ve been playing men with beards.”