Novak Djokovic, of Serbia, hits a return shot to Kyle Edmund, of Britain, during the fourth round of the U.S. Open tennis tournament, Sunday, Sept. 4, 2016, in NY.
In the day's first women's quarterfinal, Roberta Vinci fell apart after losing the opening set on a foot fault, allowing No. 2 seed Angelique Kerber to take the last nine games and win 7-5, 6-0.
Monfils, who reached his second career grand slam semi-final and first since 2008 in Roland Garros, will now meet top seed Djokovic.
The 30-year-old Monfils finished off 24th seed Pouille with his 13th ace to lead off a huge day for the French, who placed three players in the quarter-finals of a grand slam for the first time since the 1947 French Open.
Djokovic will play Gael Monfils in the semi-finals.
The Serb advanced after ninth-seeded Frenchman Jo-Wilfried Tsonga retired at the start of the third set of their quarter-final, trailing 6-3 6-2.
Tsonga said when the pain came Tuesday, "I knew it was over for me straightaway".
Indeed Djokovic - bidding to claim three majors in a year for the second straight season - wasn't concerned about rust being a factor if he had to play a fourth or fifth set in the semis or potentially, the final.
It's the world number one's third walkover in five matches at this year's tournament, and many on Twitter were quick to point out how easy his path to the last four has been.
Novak Djokovic is gunning for his 12th Grand Slam title as he continues to roll along in the U.S. Open.
Djokovic, for his part, came into this event nursing a "recurring" left wrist injury, but he's found some unexpected time for rest and relaxation in the Grand Slam considered the most grueling of the four.
He was unfazed by his sparse time on court. He never had won a U.S. Open match until last week and his 4-hour-plus win against Nadal on Sunday was his third five-setter in a row.
Louis Armstrong Stadium is scheduled to be replaced by 2018 as part of the US Open's much-needed-makeover. "That's the position where I want to be", the Serbian said.
"For sure it was affecting my play", Sevastova said, "but I'm not a person that likes to retire during a match, so I just tried my best". "I think I handled it pretty good mentally and tennistically", said Gael Monfils after reaching his first US Open semifinal. It was a match that Sania and Stryvoca really should have won, or at the very least, taken to a third set.
"As I said, this scenario. was ideal at this stage".
Said Monfils: "I have a second opportunity to get to my first slam final, and the opportunity to maybe beat him for the first time in the main tour, to beat the world No. 1". A session which began with Sevastova rolling her ankle in the second game of a 6-0, 6-2 blowout loss to Caroline Wozniacki.
Kerber has been a force to reckon in women's tennis after winning the 2016 Australian Open and reaching the finals of coveted Wimbledon earlier this year. "I just felt so good (and) it was going to be even better because it was going to be indoors".