Novak Djokovic moved within four matches of completing the first men's singles calendar-year Grand Slam in 52 years on Saturday while top-ranked Ashleigh Barty was eliminated from the US Open by a stunning fightback from American Shelby Rogers.
World number one Djokovic defeated Kei Nishikori 6-7 (4/7), 6-3, 6-3, 6-2, taking his 17th consecutive victory over the Japanese star and improving to 18-2 in their overall rivalry.
With a fourth career US Open trophy, Djokovic would complete the first men's singles sweep of major titles in the same year since Rod Laver in 1969.
Reigning Wimbledon champion Barty won 11 of 14 games after dropping the first set, only for Rogers to capture five of the last six games for a shocking 6-2, 1-6, 7-6 (7/5) triumph. Rogers had dropped all five prior meetings with Barty but would not be denied, breaking the Aussie as she served for the match in the eighth and 10th games as the crowd went wild at Arthur Ashe Stadium.
Djokovic, meanwhile, marched toward a 21st career Grand Slam title, which would break the deadlock for the men's record he shares with Rafael Nadal and Roger Federer, both absent with injuries.
The 34-year-old Serbian star advanced to a fourth-round matchup on Monday against 99th-ranked US wildcard Jenson Brooksby. Djokovic, who had 52 unforced errors and 45 winners, dropped the last three points of the first-set tie-breaker, the last on a Nishikori service winner.