Novak Djokovic, Defending Champion, Beats Gael Monfils to Enter US Open Final

Novak Djokovic downed Gael Monfils 6-3, 6-2, 3-6, 6-2 to reach a seventh US Open final Friday after a semi-final which featured booing, ripped shirts, cans of cola and thrilling shifts of momentum.

The world number one and defending champion will face either Stan Wawrinka or Kei Nishikori in Sunday's championship match where he will bid to win a third major of 2016 and 13th of his career.

But his 13th win in 13 meetings with the mercurial Frenchman will go down as one of the oddest in Grand Slam history.

In a match of high drama and controversy, Monfils was jeered for an apparent lack of effort as he threatened to capitulate in straight sets.

Djokovic, the 2011 and 2015 champion, needed treatment on each shoulder, including a medical timeout in the fourth set, as crushing humidity of 60 percent took its toll.

At one stage, the Frenchman even called for a can of cola to help summon an extra level of energy while Djokovic went into Incredible Hulk mode by ripping off his shirt in frustration on dropping the third set.

By the end of the affair, Monfils finished with 52 unforced errors while having to save 12 of 20 break points.

"Humid," said the 29-year-old Djokovic when asked to summarise the match.

"I think that's all we were thinking about and feeling in the last couple of sets. The conditions were quite different from most of the days during this tournament.

"I think at times in decisive tense moments we had many exchanges from the baseline and Gael is one of the best athletes on the tour, very flexible."

Djokovic will start as favourite in the final, holding a 19-4 lead over Wawrinka and 10-2 when facing Nishikori.

In a bizarre first set, Djokovic raced to a 5-0 lead in just 15 minutes where his only challenge came from the stadium TV lights which he claimed were distracting.

However, he was even more agitated by Monfils's curious decision to stand bolt upright inside the baseline waving his racquet airily at the ball.

Bizarre match

It looked lightweight but carried a mighty punch as the Frenchman saved four set points in the sixth and seventh games.

Monfils broke in the seventh game before the Serb regained his composure to close out the set after 36 minutes.

Djokovic was quickly 4-1 to the good in the second as Monfils's interest again appeared to wane.

By the sixth game, the 30-year-old had won just nine points which he managed to nudge into double figures by the end of it.

Monfils, playing in only his second Grand Slam semi-final after making the last-four at the 2008 French Open, theatrically hobbled off the court and was jeered.

He was roundly booed again by sections of the 20,000-strong crowd as he dropped the first game of the third set.

But Monfils is nothing if not unpredictable and the man who squandered a two sets to love lead and two match points against Roger Federer at the 2014 US Open, suddenly found the on-switch.

He broke back for 2-2 and again for 4-2 as his villain's mask slipped.

Djokovic provided added unexpected spice by requiring treatment on his left shoulder when he slipped down 2-5 and then saved a set point in the eighth game.

Monfils saved three break points in the ninth game before clinching the set, celebrating his lifeline with a mighty roar. Djokovic responded by tearing off his shirt.

Both men were struggling in the late afternoon's heavy humidity with Monfils supplementing his water intake with a can of cola at a changeover.

Djokovic was the more energised, breaking for 3-1 in the fourth set before double-faulting for a sixth time to hand it straight back.

The Serb then needed treatment on his troublesome right shoulder and took a medical timeout.

He broke for a 4-2 lead and this time held for 5-2 before securing the tie with his eighth break of the match.