Roger Federer saved two match points to defeat Gael Monfils 4-6, 3-6, 6-4, 7-5, 6-2 and reach his ninth US Open semi-final Thursday, keeping alive his dream of a sixth title.
The 33-year-old Swiss second seed, bidding to become the oldest winner of a Grand Slam title in more than 40 years, was staring down the barrel of a demoralising exit when French 20th seed Monfils had two match points in the 10th game of the fourth set.
But once they were saved, the lifeblood was suddenly sucked out of the flamboyant but unpredictable 28-year-old Frenchman whose notoriously fickle stamina failed him in a one-sided fifth set.
Victory was Federer`s 26th in 27 night-time matches in New York and put him just one win away from a career 600 victories on hard courts, a landmark he can reach if he defeats Marin Cilic to make the final.
Croatian 14th seed Cilic toppled sixth-seeded Czech Tomas Berdych 6-2, 6-4, 7-6 (7/4) earlier Thursday to reach his first US Open semi-final.
Federer`s win was his ninth from two sets to love down and first at a major since he had to engineer a similar Houdini act against another Frenchman, Julien Benneteau, at Wimbledon in 2012 on his way to his 17th and most recent major title.
“Gael played great tennis but even when I was two sets down I knew the finish line was still far away for him,” said Federer, in his first semi-final since 2011.
“I knew I could play better tennis but on match point I wasn`t feeling so great anymore.
“I just thought this could be the last point, don`t give it away on an easy shot, make him work for it.”
