I must get my head right, says Murray

Briton admits to mental failings after straight-sets defeat by world 101 in Miami

Murray has admitted that he 'wasn't myself at all' at his most recent tournaments (GETTY IMAGES)

Andy Murray has made successful comebacks from injuries and losses of form in the past, but as the Scot attempts to pick up the pieces following his worst defeat for three years he is facing another challenge. In the wake of his loss to Mardy Fish on Saturday night in his opening match at the Miami Masters, Murray admitted that he needed "to get my mind right".

Murray's 6-4, 6-4 defeat at the hands of the world No 101 was his first against a player from outside the world's top 100 since he was beaten by Fabio Fognini in Canada in 2007, when he was returning after a serious wrist injury. Since reaching the Australian Open final Murray has lost to Janko Tipsarevic in the second round in Dubai, to Robin Soderling in the quarter-finals in Indian Wells and has now fallen at the first hurdle while attempting to retain his title in Miami.

"I haven't been tough enough on the court and that's what's most disappointing," Murray said after his latest setback. "The last few weeks I've been really poor mentally."

He added: "It's not been great since Australia. I need to find a way to get round it – and I'm sure I will. I've gone through bad patches before and I just need to practise hard, work hard and get stronger. I'm sure I'll start playing better again, but the last few weeks haven't been the best."

Murray will now prepare for the European clay-court season, but he denied that a change of surface was what he needed. "I need to get my mind right," he said. "I need to get focused again. When I do that, my game will get better again, that's for sure."

The Scot could not explain why his form had deserted him. "That's something I need to sort out myself. It's purely down to me, what goes on inside my head. No one else can make that better or change it. You need to do that yourself. It doesn't matter how well you practise. You need to be tough in the matches. I need to get better mentally because since Australia, where I was great in all of the matches, I've been poor."

From 3-1 and 40-0 up against Fish, Murray fell away badly. He hit double faults at key moments, was below-par on his returns of serve and looked out of touch on his ground strokes, particularly on the forehand. Fish's ranking may have slipped following a serious knee injury, but the 28-year-old American is a big hitter who has shown in the past that he can trouble the best when his game is in order.

The defeat means Murray will lose his No 3 world ranking to Rafael Nadal next week and he is fortunate that Juan Martin del Potro, the world No 5, is currently sidelined with a wrist injury. The Scot has a large number of points to defend on clay and may return to action at next month's Monte Carlo Masters, having originally thought about missing the tournament in order to give himself more time to practise on the surface. Murray will do well to use the extra time on his hands to remind himself of the qualities that have made him one of the best players in the world. In Dubai last month the Scot admitted that he had experimented with a more attacking game style, but his natural instinct, which has served him superbly in the past, is to play as a counter-puncher.

Nevertheless, the defeat against Fish was not down to a problem with his game plan but the result of a failure to get so many of the basics right. He made a succession of errors on his ground strokes in particular and when he did find the court his shots were often short and lacking in penetration. Against an attacking player like Fish, that proved fatal.

Murray might like to take heart, however, from the experience of another player who ran into unexpected trouble in Indian Wells and Miami three seasons ago. Roger Federer lost to Guillermo Canas in the early stages of both tournaments but went on that year to win Wimbledon, the US Open, the Tennis Masters Cup and the Masters Series tournaments in Hamburg and Cincinnati.