4 September 2014 Last updated at 09:45

Andy Murray reacts to US Open defeat by Novak Djokovic

British number one Andy Murray says he "can do better" following his 7-6 (7-1) 6-7 (1-7) 6-2 6-4 defeat by world number one Novak Djokovic at the US Open.

The quarter-final loss means Murray has failed to get past the semi-finals of any tournament since having an operation on his back in September 2013.

The Scot had suffered with cramp in his first-round match last week, but said he was only able to extend Djokovic because he had trained "very hard".