Carlos Alcaraz has surrendered the number one world ranking but got his U.S. Open title defence off to an easy start as injured German Dominik Koepfer retired against the 20-year-old top seed on Tuesday.
The season's final Grand Slam began on Monday with a change at the top after Novak Djokovic demolished Frenchman Alexandre Muller to ease into the second round — a result that meant the Serb will replace Alcaraz as world number one when the rankings are updated on Sept. 11.
But Alcaraz will have the number one attached to his name for the duration of the Flushing Meadows fortnight and advanced to the second round after Koepfer twisted his ankle minutes into the match and later retired with the Spaniard up 6-2 3-2.