Emotional Coco Gauff through to US Open third round

Having brought in biomechanical coach Gavin MacMillan – the man who helped Aryna Sabalenka to overcome her serving hiccups – just days before the start of the tournament, Gauff put in a lot of extra hours on the practice court in an attempt to fix her own serving woes.

She admitted after her difficult opening match against Ajla Tomljanovic, which required three sets, that the process had been mentally exhausting and there were days when her shoulder was hurting as they tried to change her service motion.

The two-time Grand Slam winner had served 320 double faults before the start of the US Open, and she added another 10 to her tally during the Tomljanovic match.

And 330 has increased to 338 after she sent down eight more double faults during the win over Vekic in the second round with two of those coming at 4-4 in the opening set as the Croatian broke to go 5-4 up.

Gauff broke down during the changeover as she started crying, but the reigning French Open champion's never-say-die attitude helped her to battle on and she eventually won the set via a tie-breaker before settling down in the second set for a 7-6 (7-5), 6-2 win.

And there were more tears during the on-court interviews as she had to take another moment to compose herself before saying: "Honestly, today was a tough match for me, but I'm just happy with how I was able to manage.

"It's been a rough couple of weeks. I'm just happy to be back on this court, and you guys bring me so much joy. You guys really help me a lot. I'm doing this for myself, but I'm also doing it for you, and no matter how tough it gets inside, you can do it."

Gauff was broken four times in the opening set, but the good news for her is veteran Vekic also struggled and she managed to break four times herself. The second set was much better as the American broke twice and served only one double fault.

So what was going through her mind when she was struggling with her serve?

"I was just trying to tell myself to breathe, and honestly, just putting another ball in the court and just trying to remember the things that I do well," she said.

"I don't remember a lot at the end of the first set, but it's kind of amazing that I was able to get out of that one. Once I was able to reset, and went to the bathroom, splashed some water on my face, after that I felt a lot better out here."

The draw gets tougher from here on in as she faces her first seeded player in the 28th seeded Magdalena Fręch next and she gets through that, then she will take on either 15th seed Daria Kasatkina or two-time US Open champion Naomi Osaka (23) for a place in the quarter-final.