Roger Federer hit back at Boris Becker's claims his new SABR tactic was disrespectful, ahead of his US Open final against Novak Djokovic.

Federer and Djokovic, who is coached by Becker, will go head to head in the final at Flushing Meadows on Sunday after straight-sets semi-final wins.

Becker had questioned Federer's new tactic, which sees the 17-time grand slam champion step in on an opponent's serve and almost take it on the half-volley.

Asked about it after his win over Stan Wawrinka, Federer said: "Yeah, no, it's not disrespectful. Pretty simple."

After Djokovic dropped just three games against a hurting Cilic, Federer was untroubled by Wawrinka in a 6-4 6-3 6-1 victory.

An aggressive Federer said he would take plenty of confidence from his win into a meeting with Djokovic, who trails their head-to-head 21-20.

"I think Stan didn't have very high first-serve percentage in the first set, I don't think, so that definitely gave him more looks on the second serves," he said.

"But of course Stan has more power on the first serve than Novak has. It's a different server, to be quite honest, and also returns very different one to another. So I don't want to compare those two.

"I wasn't quite sure if I was going to play this aggressive against Stan, because when he's on, he presents a very different challenge to all the players I have played thus far in this tournament.

"But now that I have been able to do it also against Stan definitely gives me confidence that maybe I can also do it against Novak this way."