Not thinking about title defence: Alcaraz

Carlos Alcaraz said retaining the US Open title was not on his mind as he began the defence of his crown Tuesday with a swift win over injured German opponent Dominik Koepfer.

The world number one moved into the second round when the 75th-ranked Koepfer retired because of an ankle injury with the Spaniard leading 6-2, 3-2 under the lights on Arthur Ashe Stadium.

"That's not the best way to get through into another round," said Alcaraz, "but I have to say on my side I was playing great."

"I started pretty well. Really focused. Honestly, I didn't expect to play such a great level the beginning, the first round, here in the US Open.

"I am very, very happy with the level, even if Domi had to retire. Have to see myself and hopefully to keep that level into the next round."

Alcaraz entered a Grand Slam as the defending champion for the first time, but the 20-year-old tried to downplay the significance of being the player to beat in New York.

"I was excited to play my first round here in US Open. I mean, it was great to step on court again in the Arthur Ashe after such a great run last year. I was excited to come back," he said.

"I'm not thinking about defending the title. I was not thinking about I was the champion last year. I just focus on playing my best level, to recover the level that I played last year, try to do same things that I did last year.

"That's the only thing that I'm thinking right now. I try to be apart about all the pressure people put of me about the defending champion."

Koepfer's night was effectively cut short when he rolled his left ankle in the opening game of the match, and required a medical timeout.

He gamely fought on for an hour before eventually accepting his fate, not wanting to further aggravate the injury.

"Being on Ashe, playing against Carlos for the first time. Probably the biggest match I've played in my tennis career so far," said Koepfer.

"It's by far the coolest experience I've had, up to deuce in the first game. It didn't last long but still you want to soak those moments up and I wanted to try my best.

"I can't say I didn't try. I took painkillers, got it taped, but it got worse and worse. There's no point in ruining the rest of the year."

Alcaraz will play big-serving South African Lloyd Harris for a place in the last 32.

He will surrender top spot to Djokovic after the US Open but admitted he was eager to reclaim the number one ranking before the end of the season.

"Well, right now it's a goal for me honestly. I said before that we are having a really good battle for the No 1, Novak and I," said Alcaraz.

"I knew that he was going to recover the No 1 after US Open. When the tournament is over, I will try to recover as soon as possible. That's my goal. I am working for that.

"The season has a lot of tournaments until the year is over. I'll try to recover it before the year ends."