Carlos Alcaraz said on Friday he feels at "100%" ahead of his defense of the US Open, but acknowledged feeling anxious after a four-month layoff due to a wrist injury.

The Spaniard has drawn confidence from grueling practice sessions ahead of the Grand Slam, he told reporters at a pre-tournament media day.

"I need to come here to practice with these guys to to feel the competition once again, and this is a real a real testing," he said.

"I'm feeling great and ... that helped me a lot to to know right now that it's all in my head," he said.

Alcaraz, 23, the youngest player to win the career Grand Slam after triumphing in Australia in January, hasn't played singles since 16 April, withdrawing from the Barcelona Open with a right wrist injury and subsequently skipping both the French Open and Wimbledon.

Alcaraz, who partnered Serena Williams in the US Open's mixed doubles event on Tuesday, told reporters on Friday that his coaching and support team had complete confidence that he was ready to go.

"I gotta trust my people that tell me that it's gonna be fine. So I just have to go 100 percent," he said. "So I'm just trying to to like stay away ... from that fear."