Like most tennis players for whom superstition is second nature, Andy Murray claims never to look too far ahead when it comes to his draw, wary of the pitfalls that lie at every round.

However, as he prepares for his fourth-round match at the Sony Ericsson Open in Miami today, even the Scot will know he has been presented with a golden opportunity to make some serious inroads in the tournament.

As the No.4 seed, Murray is well used to competing at the business end of Masters 1000 events – he has won eight of them in his career – but after his early loss in Indian Wells, any gifts will be gratefully accepted.

Having already received a walkover against Milos Raonic because of an injury suffered by the Canadian, Murray will be keeping his ears open for any news of the condition of today's opponent, Gilles Simon. One of the fittest players on tour despite the slightest of frames, the Frenchman has been struggling with a back injury for some time and only just made it through against Austria's Jurgen Melzer in the previous round.

"I know I have no chance to win if I am not 100 per cent, so that will be my first challenge in this match," Simon said after finishing the job in some discomfort. "I have a lot of troubles. I have had some pain in my back the last year. I always have some troubles and now I have one more. I managed to win this one, but it's not a good sign for me. I have a lot of work to do."

Having only played one match in Miami so far, a loss of sharpness may pose the biggest threat to Murray but the Scot is experienced enough to stick to his routine and prepare in the same way as usual.

As the world No.13, Simon presents many of the world's top players with several problems but Murray has dominated their head-to-head record, losing their first match but winning all eight since. In essence, Murray is a bigger, stronger and more versatile version of Simon, which means he is slightly better in every department.

When Murray played Simon in Monte Carlo last year, when the Frenchman was again ailing, the Scot was even booed by sections of the rather unique Riviera crowd when he threw in more drop shots than usual to test his opponent's fitness.

It is a tactic Murray will not hesitate to use again today, if required, and with world No.7 Tomas Berdych also gone from his section of the draw, he will have one eye on a potential semi-final tie with No.2 seed Rafael Nadal.

The 24-year-old will also have been an interested spectator last night, with fellow Britons Colin Fleming and Ross Hutchins due to play India's Leander Paes and Czech Radek Stepanek for a place in the quarter-finals of the doubles event.