NEW YORK, Aug 30, 2023 (BSS/AFP) - World number one and defending champion Carlos Alcaraz moved into the second round of the US Open on Tuesday as his German opponent Dominik Koepfer retired with an ankle injury.

Alcaraz was leading 6-2, 3-2 in the night session on Arthur Ashe Stadium court when the 75th-ranked Koepfer, who rolled his ankle in the opening game of the match, decided to throw in the towel.

"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."

The 20-year-old Spaniard will play big-serving South African Lloyd Harris for a place in the last 32.