Novak Djokovic crushed US Open champion Marin Cilic on Arthur Ashe Stadium, routing their semi-final 6-0 6-1 6-2 on Friday.

In the aftermath of Serena Williams' shock loss in the women's semis, Djokovic's performance restored the status quo somewhat - but the absence of any resilience from Cilic was the big surprise in the first of the men's last-four battles.

Djokovic was on and off the court in just one hour, 25 minutes, and in a post-match interview defended Cilic - claiming his opponent was blighted by an ankle injury in recent days.

For just the second time in 14 career meetings, Djokovic served up a bagel set to Cilic - who was getting crushed on his second serve.

By the time the Croatian got on the scoreboard - he held for 1-1 in the second set - he had won just three of 19 points after he missed his first serve.

Credit had to go the way of the world number one, though, who was duly reminded about the realities of professional tennis with Serena's shock loss - but showed no such nerves himself in a clinical performance.

On serve, Djokovic stumbled only once - when he gave back a break lead, only to regain it immediately - while holding to either love or 15 nine times.

Cilic, meanwhile, hit 37 unforced errors in what was his fourth submission to Djokovic since challenging him in five sets at Wimbledon in 2014.

The ninth seed's second serve was a major problem, and Cilic's desire to go for a little more behind it led to double faults at break points in each of the first two sets.

Djokovic was challenged in set three when Cilic broke back for 2-2 from a 40-15 deficit, but the nine-time major winner immediately responded - and from 3-2 up, he lost just one point on his way to earning three match points.