Roger Federer has admitted that he feels the 2018 US Open is "the slowest in years."

The 37-year-old Swiss veteran, who is aiming for his sixth Grand Slam title at Flushing Meadows, will play Australian Nick Kyrgios in the third round of the tournament.

And the Basel-native, who beat Frenchman Benoit Paire at the Arthur Ashe Stadium in straight sets with a 7-5, 6-4, 6-4 triumph, has been vocal in his views of the competition this year.

Federer, who won the Australian Open in Melbourne at the beginning of the season, has been surprised by the condition of the courts which are considered to be playing much than in recent years.

"It is hard to play free, just every time. You do care about the outcome of the match. You do care about each and every point," Federer admitted. 

"Not the same, like a break-point, is not the same importance like a 40-Love point. Sometimes you don't play as good in a first round. Sometimes, like in Cincinnati, you have days where you're happy to make shots.

"Then you have other days, like in other finals, because you're playing so good, you're like, In which corner shall I put it tonight? It also varies on how you're feeling.

"But I think playing free is meaning, for me anyhow, to play without fear, like there to take chances, but probably controlled aggression, I'd like to call it. Not play too safe, but at the same time, you don't want to be silly and play sort of with no plan.

"It always has to have a plan for it. I think it's especially important when you're actually feeling good, the score is tight, for me is to remind myself then at that very moment how exactly I want to play and not to freeze and not to feel too much pressure at that moment."