The pair of China's Zhang Shuai and Australia's John Peers shrugged off the first set down, rallying to edge out American Nicole Melichar/Austrian Oliver Marach to advance into the U.S. Open mixed doubles semifinals on Monday.
The none-seeded Zhang/Peers upset Melichar/marach, the second seed, 3-6, 7-6 (7), 11-9 in one hour and 44 minutes.
It is the first time that Zhang, 29, entered the top four of a Grand Slam tournament.
So far, Zhang is also in the U.S. Open women's doubles quarterfinals with her Australian partner, Samantha Stosur. They will take on Russian Anstasia Pavlyuchenkova/Latvian Anastasija Sevastova to vie for a semifinal berth.
Zhang had ever competed in the women's singles, but were eliminated in the first round by 12th seed Garbine Muguruza from Spain.
Peers, 30, is ranked 4th in the doubles now.