NEW YORK (AP) -- Normally, someone must win five full matches to reach a Grand Slam semifinal. Novak Djokovic has made it that far at the U.S. Open by playing only two complete matches, because three opponents pulled out of the tournament with injuries.
Djokovic, the No. 1 seed and defending champion, once again needed to put in very little work, advancing to the final four at Flushing Meadows for the 10th consecutive year when No. 9 Jo-Wilfried Tsonga stopped because of a hurt left knee Tuesday night.
The first two sets of their quarterfinal went Djokovic's way, 6-3, 6-2. At the ensuing changeover, Tsonga was visited by a trainer and had his left leg taped below the knee. They played one point to begin the third set: Tsonga double-faulted, then retired from the match.
This came after Djokovic's second-round opponent, Jiri Vesely, withdrew from the tournament with a sore left forearm. And then the man Djokovic was supposed to play in the third round, Mikhail Youzhny, quit after six games and only 31 minutes with a strained left hamstring.
"I put myself in a position again to be one match away from the finals. As tournament progresses, I feel like I'm getting better," Djokovic said. "Of course, this Grand Slam is very unique for me: I never experienced something like this -- to have three retirements on the road to the semifinals."
On Thursday, Djokovic will play No. 10 Gael Monfils, who advanced earlier against No. 24 Lucas Pouille, the man who eliminated Rafael Nadal in the fourth round. Playing steadily, and with only a dose of the spectacular, Monfils reached his first major semifinal since 2008 by beating an error-prone Pouille 6-4, 6-3, 6-3 in an all-French quarterfinal.
For all of his deep runs at Flushing Meadows, Djokovic has won only two of his 12 Grand Slam titles at the hard-court tournament, in 2011 and 2015. He's lost in four finals and three semifinals over the past decade.
It's tough to know exactly how well he's playing at the moment, simply because no one has seen him on court all that much lately: less than 6 1/2 hours through five rounds.
After his run of four consecutive major championships -- the first time a man had done that in nearly 50 years -- was capped by his initial French Open title, Djokovic was upset in the third round at Wimbledon. He returned to action by winning the Toronto Masters, but since then, Djokovic lost in the first round of the Rio Olympics while dealing with a sore left wrist that he then cited in skipping the Cincinnati Masters.
Djokovic's right arm was massaged by a trainer in his first- and fourth-round matches at the U.S. Open, so getting all of these free passes hasn't been a bad thing.
"In this stage of the season, considering some physical issues I have had in the last month, month and a half, this was the scenario that I needed and I wished for. I got a lot of days off and recovered my body," Djokovic said. "Right now, I'm feeling very close to the peak. That's the position where I want to be."
And that's a scary thought for Monfils. When Djokovic is at his best, his returns, court coverage and groundstrokes are as it good as it gets in today's game.
Monfils, who turned 30 last week, only once before made it to a Grand Slam semifinal, 8 1/2 years ago in front of a partisan crowd at the French Open. But he has been fanstastic during this tournament, winning all 15 sets he's played.
"I love watching Gael. He's one of the few players that I will definitely pay a ticket to watch," Djokovic said. "He's very charismatic. Plays with a smile. Enjoys tennis. Enjoys life."
Pouille quite simply ran out of steam, winding up with just about three times as many unforced errors as Monfils, 44-15. Pouille never had won a U.S. Open match or any match that lasted five sets until last week; his 4-hour-plus win against Nadal on Sunday was his third five-setter in a row.
No one ever has won four consecutive five-setters at a major in the Open era, which dates to 1968.
"Of course," Pouille said, "I was a bit tired today."
All in all, the spectators with tickets for Tuesday did not get much competitive or quality tennis. All four matches were decided in straight sets -- or, in the case Djokovic vs. Tsonga, even fewer.
In the 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. In the other, two-time runner-up Caroline Wozniacki was a 6-0, 6-2 winner against Anastasija Sevastova, who injured her right ankle in the second game and was never able to get going.
