Coco Gauff bursts into tears at US Open as she struggles to fix serve during brutal second-round match

Double faults and unforced errors plagued Coco Gauff's game as she scraped through the first round of the US Open by the skin of her teeth earlier this week. And that distressing theme continued to a troubling extent when she returned to Arthur Ashe Stadium on Thursday night.

So much so, in fact, that the 21-year-old was reduced to tears when consecutive double faults resulted in a gut-wrenching break which left her trailing Croatia's Donna Vekic 5-4 in the opening set of their second-round match.

A visibly distraught Gauff covered her face with a towel after taking her seat on the sideline while overcome with emotion. Having recently brought on board Gavin MacMillan - the biomechanics expert who cured Aryna Sabalenka's serving crisis to help her become the top-ranked player in the world - this was not supposed to happen.

She then had more time than expected to mull over her misfortunes when Vekic took a lengthy medical timeout for treatment on her shoulder. And when they got going again, it was the Croatian who let mistakes sully her game as she too suffered a frustrating break to level proceedings at 5-5. 

Yet just as momentum looked to have shifted, two more consecutive doubles left Coco in ruin once more.

That all changed when the reigning French Open champion dug deep to draw level again at six apiece, before showing her elite-level resolve by prevailing in the tiebreak.

And after edging the first, it was Vekic who capitulated in a one-sided second set as Gauff clinched a 7-6, 6-2 victory to advance to the third round.

The lump in her throat that emerged after the first consecutive double faults had clearly remained throughout the match. In her post-game interview on court, Gauff broke down in tears again before saying: 'Today was a really tough match for me. It's been a rough couple of weeks.'

It is unclear what exactly Gauff has been battling of late. Though while she again looked a shadow of her former self at times, the significant improvement in the second set should be enough to restore some vital confidence ahead of her third-round match this weekend.