Andy Murray has admitted that missed opportunities cost him in his fourth-round defeat to Kevin Anderson at the US Open.

The world number three crashed out of the competition as the South African overpowered him with his serve and groundstrokes at Louis Armstrong Stadium to clinch his place in the quarter-finals of the competition.

Murray has conceded that he was not able to take his chance to get back into the match after losing the first set, which made life even tougher for him against an in-form Anderson.

He told reporters: "I was playing against an excellent player. I was on the back foot quite a lot and I was not able to play offensively, but when you're playing against someone that has the game style that he does you're always going to have to do your fair share of defending.

"Tonight he served extremely well. The service game I played at 4-1 down [in the second set], I was up 40-love, got broken. That was around the time when I was starting to get the momentum a bit back on my side.

"I broke him straight after that, held serve, then had break points the next game. Maybe if I'd held serve at 40-love, I might have been able to snatch that second set. From there I fought hard through to the end."

Murray's defeat ended his run of 18 consecutive Grand Slam quarter-finals, a spell stretching back to 2010.