Defending champion Coco Gauff says she is treating this year's US Open as a "victory lap" after comfortably beating Varvara Gracheva in her opening match.

Gauff, 20, began her title defence with a 6-2 6-0 victory in just 66 minutes on Arthur Ashe Stadium.

The American beat Aryna Sabalenka in last year's final to win her first Grand Slam and followed that by reaching the semi-finals of the Australian Open and French Open this year.

But she has struggled for form recently, losing in the third round of the Paris Olympics before suffering early exits at tournaments in Cincinnati and Toronto.

Gauff said the past few weeks have "been a little bit tough", but she believed her performance against Gracheva was "the best tennis I have played in a while".

She added that a fan's comment on her TikTok account had helped change her perspective coming into the US Open.

"Someone commented on my TikTok saying you've won in life, literally and figuratively, and there's no point in piling pressure on yourself on a victory lap," Gauff said in her on-court interview.

"I'm just treating this tournament like that and if you defend something that means you won something."

Gauff, who fired down 10 aces, broke Gracheva's serve twice in the opening set and won the last nine games on her way to an emphatic victory.

She will face German veteran Tatjana Maria in the second round after the 37-year-old moved past Argentine qualifier Solana Sierra 6-2 6-3.