Tennis pro Dominik Koepfer has advanced to the second round of the ATP tournament in Washington.
The world number 145, who entered the main draw as a qualifier, defeated the South Korean Kwon Soon Woo (ATP 77) after 2:21 hours 3: 6, 6: 3, 6: 4.
In the second round, Koepfer, who was 4-1 behind in the decisive set, meets Karen Khachanov, who is number seven. At the two previous US tournaments in Newport (grass) and Atlanta (hard court), Koepfer failed because of his opening opponent.
Peter Gojowczyk is still in action against Frenchman Benoit Paire in Washington on Monday.
The tournament is part of the North American hard court season, which culminates with the US Open starting August 29 in New York.