BIG PREVIEW: Novak Djokovic favourite as pretenders line-up at US Open semi-finals

New York: Novak Djokovic heads into the US Open semi-finals as the overwhelming favourite to go on and lift a third title in New York, but Kei Nishikori, Stan Wawrinka and Gael Monfils are potential road blocks.

World number one Djokovic takes a 12-0 career lead over Monfils into their semi-final on Friday while Nishikori looks to build on his shock five-set win over Andy Murray against Wawrinka.

Swiss third seed Wawrinka, playing in his third semi-final in four years, ended Juan Martin del Potro`s magical run in the early hours of Thursday morning with a four-set win.

World number one Djokovic, chasing a third major of the season and 13th overall, remains wary of the dangers posed by 30-year-old Monfils who is in only his second semi-final at the Slams.

"Gael`s one of the few players that I will definitely pay a ticket to watch," said Djokovic.

"He seems more focused at this time of his career and I am definitely expecting a tough battle."

Tenth-seeded Monfils has lost twice to Djokovic in New York -- in five sets in the first round in 2005 and a straight sets defeat in the 2010 quarter-finals.

But he is enjoying one of the best spells of his career, winning the title in Washington and making the semi-finals at the Toronto Masters where he lost to Djokovic again.

Monfils is on an impressive 19-2 run since Wimbledon but admits he`s the underdog against Djokovic, the 2011 and 2015 champion playing in a 10th successive semi-final in New York.

"He`s better player than me, definitely," said Monfils who has yet to drop a set but hasn`t faced a seeded player.

Djokovic should be the fresher having completed just two full matches in five rounds.

He was handed a walkover into round three and was then the beneficiary of two injury-hit retirements.

All of which means the Serb has spent just 4 hours and 34 minutes on court; Monfils has been out there four minutes short of 12 hours.

Nishikori reached the semi-final -- his first at any Slam since he finished runner-up in New York in 2014 -- with an impressive 1-6, 6-4, 4-6, 6-1, 7-5 triumph over world number two and 2012 champion Murray.

It was just his second win in nine matches with the Briton but he is happy chasing down deficits.

Against Wawrinka, he trails 3-2 but won their last meeting in the Toronto semi-finals this summer.

He also beat the 31-year-old in five sets in the quarter-finals of the US Open in 2014.

"We just played in Toronto. He`s been playing good tennis," said Nishikori who has a double target this weekend.

He can become Asia`s first Grand Slam men`s singles champion while the title would net him a windfall of $3.5 million.

Nishikori will be happy not to be facing del Potro who has a 4-0 lead in their rivalry and has never conceded a set to the Japanese.

Wawwrinka has had a roller-coaster run to the semi-finals.

In his first five rounds he did not face an opponent inside the top 45 while he had to save a match point to beat Britain`s Dan Evans in the third round.

"It`s going to be interesting for sure against Kei," said Wawrinka, the late bloomer of the men`s tour who only reached his first quarter-final of a Slam at the 23rd attempt in the 2010 US Open.

"I saw him play against Murray. He was playing really well. It`s going to be tough match, for sure. We will see also how I`m going to feel physically. But, yeah, I`m ready for a match against Kei."

With second seed Murray, fourth seeded Rafael Nadal and Milos Raonic, the fifth seed, all out of the picture, Djokovic is viewed as the most likely to win the title on Sunday.

"I`d say Novak would be the favourite," said Murray.