World number two Andy Murray was very happy with his performance after he eased into the US Open quarter-finals on Monday.

Murray was a class above against fellow seed Grigor Dimitrov, cruising to a 6-1 6-2 6-2 victory at Arthur Ashe Stadium in New York.

Olympic gold medallist Murray was virtually impenetrable as Dimitrov struggled, tallying 28 winners and just 23 unforced errors compared to his 22nd-seeded opponent, who was 13 and 43 for the match.

"I played very well. Tactically I played a very good match. I don't think I made any mistakes there. I kept good concentration throughout," Murray told reporters ahead of a last-eight showdown with Kei Nishikori.

"It was a really good match. I think Grigor played his best, but I didn't really give him a chance to get into the match."

After initially going toe-to-toe with Murray in the opening games, Dimitrov lost his way and continued to look out-of-sorts as the match progressed.

About Dimitrov's struggles, Murray said: "I think that helped. I mean, I don't think he started the match, like, really badly. He had a couple of breakpoints in the first game. I don't think he started, like, really badly.

"But once I got up in the score, wasn't giving him any free points, I could sense it was getting tough for him. I just wanted to keep my foot on the gas, which I didn't really do the other day. That was the one thing that I wasn't happy with against [Paolo] Lorenzi. When I did win a first set that was tight, didn't play my best, I kind of let him back into the match after I got a break early in the second.

"I wanted too make sure today if I got ahead, I stayed on top of him, I didn't have any dip in concentration or my level, and I stuck to my tactics that were working well. That was it.

"It's easier for him to him to answer how he felt about the situation or the occasion. I just know from my side, I didn't give him an opportunity once I was ahead to let him back in the match."