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.

After taking her seat on the side of the court a visibly distraught Gauff covered her face with a towel 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 world's No 1 player - this was not supposed to happen.

She 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 before 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 as she slipped 6-5 behind, again leaving her one game away from falling a set down.

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

What exactly has been throwing Gauff off her game of late remains unclear. While she registered a worrying 59 unforced errors against Ajla Tomljanovic on Tuesday, a reduced count of 18 here is a sign of encouragement for her.

Nevertheless, after 10 double faults in the first round the 2023 US Open champion still put up eight against Vekic - including that pair of consecutive serving gaffes which lost her the game on each occasion.

Her opponent on Thursday night encountered similar difficulties, recording 36 unforced errors herself. When Gauff got her act together in the second set, where she had only five compared to 13 in the opener, there was only one winner as Vekic came off second best in the majority of rallies.

Even in the second set which she won at a canter, Coco appeared to merely be hanging in there and waiting for a mistake to come from the opposite end of the court. She was still strikingly far from her best, yet that will almost provide encouragement after cruising it 6-2.