Serena Williams has advanced into the second round of the US Open with a 6-0 2-0 win after Vitalia Diatchenko retired early in the second set.
The reigning champion, who is hunting a fourth straight title at Flushing Meadows, had won all eight games before an ankle injury forced the Russian to retire.
The American and world number one barely broke sweat in the first set, inflicting three breaks of serve en route to winning the opener in just 23 minutes.
Diatchenko, ranked 86th in the world, then received medical treatment on her ankle for a second time in the contest, before retiring having won just five points in the match.
Williams will face Kiki Bertens of the Netherlands next.
