Murray keeps eye on rankings in Miami

(GETTY)

Andy Murray insists that winning a Grand Slam tournament remains his overriding goal but as he prepares to defend his title at this week's Miami Masters the 22-year-old Scot may also be keeping his eye on the world rankings. Despite swapping places with Rafael Nadal in yesterday's updated list to return to No 3, Murray will be more aware of the benefits of maintaining his healthy lead over Juan Martin del Potro, the world No 5.

Dropping temporarily out of the top four earlier this year meant that Murray had to play Nadal in the quarter-finals of the Australian Open, even if the Spaniard was unable to stop his progress towards the final in Melbourne. Del Potro's injury problems – the Argentine has not played since January because of a wrist injury and will not be in Miami – mean that he cannot overtake Murray during the next fortnight, but the Scot knows that this is the last tournament on his favoured hard courts before the start of the clay-court season.

Murray, who will play his opening match on Friday or Saturday, dropped ranking points by losing to Robin Soderling in the quarter-finals in Indian Wells last week and will need a good showing in Miami if he is to stay ahead of Nadal, who has only quarter-final points to defend.

In reaching the semi-finals in Indian Wells on his return from a knee injury Nadal went further than any of his top four rivals. He lost to Ivan Ljubicic, who won his first Masters Series title at the expense of Andy Roddick. The Croat is back up to No 13, his highest position for three years.

Jelena Jankovic, who started last year as world No 1, climbed back a place to No 8 following her victory in the Indian Wells final over Caroline Wozniacki.