Roger Federer saved two match points while coming all the way back from a two-set deficit to beat Gael Monfils 4-6, 3-6, 6-4, 7-5, 6-2 Thursday night and reach the U.S. Open semifinals for the first time since 2011.
Frustrated by Monfils' unpredictable style, flummoxed by the swirling wind, and missing shots he normally makes, Federer twice was a single point from losing while down 5-4 in the fourth set.
But he got out of that hole, starting a five-game run that put the match in his control for the first time all evening. It helped that Monfils' quality of play dipped, including what wound up being a total of 10 double-faults.
This was the ninth time Federer has won a match after dropping the opening two sets.
The 20th-seeded Monfils was trying to reach his second career Grand Slam semifinal. Instead, Federer advanced to his 36th, ninth at Flushing Meadows. Five of Federer's record 17 major singles titles have come at the U.S. Open, but he exited in the quarterfinals in 2012, and the fourth round in 2013.
On Saturday, the second-seeded Federer will play 14th-seeded Marin Cilic of Croatia. The other semifinal will be No. 1 Novak Djokovic against No. 10 Kei Nishikori; their quarterfinal victories came Wednesday.
Cilic wasn't allowed to play in last year's U.S. Open, forced to the sideline by a four-month doping suspension that he says he didn't deserve. But Cilic reached the second Grand Slam semifinal of his career, and first since 2010, by beating sixth-seeded Tomas Berdych of the Czech Republic 6-2, 6-4, 7-6 (4) Thursday.