NEW YORK >> For quite a while, Novak Djokovic's opponent in the U.S. Open semifinals, Gael Monfils, looked as if he didn't want to win — or even be there at all.

That premeditated "great strategy" of hoping to lull the No. 1 seed and defending champion into complacency and mistakes, as Monfils described it later, worked briefly, yet did not prevent a two-set deficit. So he transformed back into his entertaining, athletic self. A sweat-soaked Djokovic sought help from a trainer for aches in both shoulders, and what was no contest suddenly became one.

Monfils forced a fourth set, and Djokovic ripped off his white shirt angrily a la "The Incredible Hulk."

The ultimate outcome was only briefly in the balance, though. Djokovic regained the upper hand, as he so often does, reaching his 21st Grand Slam final and seventh at the U.S. Open with an eventful and, at times, bizarre 6-3, 6-2, 3-6, 6-2 victory over Monfils on Friday.

"Well, it was a strange match," said Djokovic, in the understatement of the tournament, "as it always is, I guess, when you play Gael, who is very unpredictable player."

Never more so than on this muggy afternoon, with the temperature at 90 degrees and the humidity above 50 percent. Monfils, now 0-13 against Djokovic, spent most of his news conference defending his unusual approach and said he knew beforehand he might try it.


On ESPN's telecast, John McEnroe blasted the 10th-seeded Frenchman for lack of effort; the Arthur Ashe Stadium jeered him.

"First question is, like, 'You're not competing?' ... Yes, I'm competing," Monfils said, cursing for emphasis. "I made a sign to my coach (to) say, 'OK, I'm going to Plan B."'

Djokovic raced to a 5-0 lead and earned a set point after all of 19 minutes, but Monfils held there. With Djokovic in possession of three more set points while serving at 5-1, 40-love, Monfils transitioned into something that might have appeared to be an attempt to "tank" — in other words, lose on purpose, for who knows what reason — but which he explained afterward was the tennis equivalent of Muhammad Ali's boxing "rope-a-dope," absorbing someone else's best shots and pretending to not be interested in attacking.

Instead of his usual crouch preparing to return serves, alert and with elbows on knees, Monfils casually stood upright at the baseline, without a worry in the world, looking like someone waiting to place his takeout espresso order. During points, Monfils would hit slices or make truly halfhearted, half-swinging strokes, then occasionally wallop a 100 mph passing shot. Monfils even repeatedly tried serve-and-volleying, a style he almost never employs, and erred often.

"I (had) to change. That's a little bit tough, because, for sure, people are not really ready to see that," Monfils said. "Definitely, I try to get in his head, try to create something new for him to see."

Somehow, the tactic was effective for a bit.

Miscue after miscue started coming from Djokovic, and Monfils won three games in a row, before eventually dropping a set for the first time all tournament.

"I was completely caught off-guard," Djokovic acknowledged.

Prodded by reporters about what he thought of the way Monfils played, Djokovic said, "I thought, at times, that he was maybe behaving a little bit — for some terms and judgments — unacceptable. But I guess that was part of his tactics. If he said that you have to believe him, I guess."

Djokovic entered Friday having enjoyed the easiest path to a major semifinal in the nearly half-century of the Open era: Three of his first five foes pulled out of because of injuries. Then came this 21/2-hour miniseries, topping them all for oddness.

On Sunday, Djokovic will try for his third U.S. Open championship and 13th major trophy overall, facing No. 3 Stan Wawrinka or No. 6 Kei Nishikori.

Safe to say, nothing the rest of the way is likely to be as intriguing as Djokovic vs. Monfils.

In the second set, Monfils lost five games in a row and 20 of 24 points in one stretch, and came up limping afterward. Soon enough, Djokovic went up 2-0 in the third, breaking on a double-fault that drew boos and whistles. All over but the shouting, right? Nope. In a blink, Monfils suddenly came to life. When he broke back to get to 2-all, he raised his right fist and the fans roared, now backing him.

Monfils won five consecutive games, including one spectacular point in which he took a long run to get to a short ball, then reversed direction for a leaping volley winner.

Hours before the match, Djokovic clutched at his back during a practice session in Ashe. Behind 5-2 in the third against Monfils, Djokovic got his left shoulder massaged. Later, it was time for help with the right shoulder during a medical timeout. By the end, he was hitting second serves in the low 80s mph or below. These would constitute new trouble spots for the Serb, who arrived in New York with concerns about his left wrist, then got treatment on his right elbow during his first- and fourth-round matches, the only ones he needed to complete until Friday.

Asked what worries he might have about his health, Djokovic replied, "Thankfully, it's behind me. So I don't have any concerns."

The man Djokovic was supposed to play in the second round, Jiri Vesely, withdrew a couple of hours beforehand, citing a left forearm problem. In the third round, Mikhail Youzhny quit after six games across 31 minutes because of a strained left hamstring. In the quarterfinals, Jo-Wilfried Tsonga stopped after two sets plus one point with a hurt left knee.

This time, Monfils was leaning over and using his racket like a cane for support between points in the third and fourth sets. More examples of playing possum? Perhaps. But Djokovic showed his own signs of distress in the energy-sapping conditions.

After all of that, Djokovic will play Sunday for his third Grand Slam championship of the season, after those at the Australian Open in January, and the French Open in June — when the theatrics were at a relative minimum by Friday's standards.