When Andy Murray lifted the famous Wimbledon trophy last July, he secured himself a place in the pantheon of British sporting heroes.

Becoming the first British man to triumph at the All England Club since 1936 led many to believe that 2014 would represent a three-way battle between Murray, Rafael Nadal and Novak Djokovic for the world number one ranking. 

A tame defence of his US Open title and an injury-forced hiatus halted plans for supremacy in 2013, and a disrupted off-season worsened any chances of victory at the Australian Open in January.

However, of all the so-called "big four", Murray's season thus far has been the most disappointing. 

Outclassed by a rejuvenated Roger Federer in Melbourne following an early loss in the season-opening event in Qatar, Murray lost in the semi-finals of the event in Acapulco to Grigor Dimitrov in three sets. Whilst his record in Indian Wells is less than inspiring, his laboured second round win over Lukas Rosol in California posed many questions.

Having missed a significant part of the autumn, Murray's ranking is now under threat.

He has 1,000 ranking points to defend from the Miami tournament to be staged following the Indian Wells event, and will harbour few hopes of accumulating a considerable number of points during the clay-court season.

He then has over 2,000 points to defend during the grass-court season, having triumphed at Queen's prior to his famed victory at SW19. Therefore, this event in Indian Wells is crucial to Murray's immediate position in the top ten.

Although Murray will be heartened by his third-set performance against Rosol, the first two-sets were often in the hands of the Czech, and his defensive game may leave him vulnerable to more consistent big-hitters, such as Tomas Berdych and Jo-Wilfried Tsonga.

If Murray is to contend for the biggest prizes this year, he must become more expressive in his tennis.

Against Federer in Melbourne, the Scot was far too passive, and lacked his usual consistency.

In Indian Wells Murray forced Rosol to self-destruct, but for all Murray's tenacity, the Czech will feel this was the one that got away.

Murray fans will point to the Wimbledon champion's injury-hit preparations to the current campaign, but if Murray is to be considered a genuine member of the "big four", he must be compared against the other members of the elite quartet.

Nadal's storied comeback from injury last year demonstrated that the true titans of the sport can return as if they had never left. 

Murray and Nadal could meet in the quarter-finals this week, and that will prove the ultimate test.

If Murray's return is to gather pace, he must prove himself against the true comeback specialist.

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