Novak Djokovic stayed on course for back-to-back Grand Slam titles by beating Kei Nishikori to set up a US Open final against Juan Martin del Potro.

With conditions much cooler than they have been for most of the tournament, Djokovic finally looked comfortable on Arthur Ashe Stadium and responded with his best performance to defeat Nishikori 6-3 6-4 6-2.

The sixth seed will contest an eighth US Open final looking for his third title and 14th overall at slams, which would put him level with Pete Sampras.

Djokovic said: “It felt great. I thought I came in today from the first point with a great intensity, great focus.

“You have to execute the shots against Kei Nishikori, who is one of the quickest movers.

“You’ve got to make decisions really quick and I thought I played really, really well.”

It was the ninth consecutive slam semi-final that the 31-year-old has won and sends him through to a 23rd final.

“It means the world to me,” he said. “Every time I accomplish something big I see a new mountain top around the corner. I don’t see any limits.”

Nishikori beat the Serbian at the same stage here four years ago but had lost all 13 meetings since and never looked like threatening a repeat performance from the moment Djokovic broke in his opening service game.

If there were still any question marks after he won Wimbledon this summer about whether this was Djokovic back to his best, they are surely gone now.

The fire is burning brightly and, now the 31-year-old’s shoulder problems appear to be behind him and his confidence in his game has returned, he once again resembles a brick wall on very speedy legs.

Nishikori’s only real chance came at the start of the second set when, having survived a long game on his own serve, he had two chances to break the Djokovic serve – his only break points of the match.

But he could not take either and, once Djokovic broke to lead 3-2, it merely seemed a question of how much resistance his opponent could muster.

Nishikori was hoping to join Naomi Osaka in the finals and make it an even more historic week for Japan and he continued to fight his hardest, but Djokovic had an answer to nearly everything.

And he saved the best for last, arrowing a backhand winner into the corner from well outside the court to wrap up the victory after two hours and 22 minutes.