After playing in pain – eventually in vain – at the Davis Cup last month, Murray decided that the tendinitis in his left wrist that first cropped up in the weeks leading up to the US Open would benefit more from a couple of weeks extra rest than from being tested by the demands of a top-level event, namely this week’s Masters 1000 event.

World No.1 Roger Federer also chose not to come to Shanghai but the rest of the world’s best have all gathered, and that could spell trouble for Murray. The 22-year-old is already resigned to losing his world No.3 spot to Novak Djokovic a week today and, while that will not worry him unduly, he will surely be monitoring the performance of Juan Martin Del Potro, the US Open champion, who would be breathing down his neck should he win the title here.

While being No.3 or No.4 makes little difference to the difficulty of a player’s draw, on paper, dropping to No.5 would be more problematic because it would open him up to the risk of facing two of the top three seeds in the semi-finals and final of a grand slam event.

Del Potro has fewer ranking points to defend than Murray until the end of the season and though Djokovic has points to defend at next month’s ATP World Tour Finals in London, the Scot may have to fight hard to retain his place in the top four.

While Murray’s quest for a grand slam title will get its next outing in Australia in January, Del Potro has already broken through and admitted that overtaking Murray in the rankings would be “a good idea”. But there is a wise head on his 6ft 6in frame and he knows that the big events are the key.

“I don’t think too much of the ranking,” he said, “I just want to improve my game and try to beat them [Federer, Nadal, Murray and Djokovic], because if I beat them in every tournament [my ranking] will be better. If I finish the year maybe 4, 3, it could be better but if I finish 6, 5, anyway, it would be a good season.”

Should Murray one day go on to win Wimbledon, the inevitable hysteria would nevertheless do well to match the one Del Potro received when he returned home to his home city of Tandil after his US Open triumph last month. Football is a religion in Argentina but tennis had its day as Del Potro was treated like royalty, addressing a large crowd including most of his family, to the point where he felt “like the president”.

“It was an unbelievable moment coming back to Argentina, my home town and seeing my parents, family, friends and all my city, walking around the street with me,” he said. “It was like a dream. It was a very heartening moment, very strong. For sure I will never forget that moment.”

Del Potro opens his campaign with a second-round match against either Austrian Jurgen Melzer or Jeremy Chardy of France. Rafael Nadal tops the seedings ahead of Djokovic, who will be chasing a second straight title, after a 6-2, 7-6 (7-4) win over Marian Cilic at the China Open yesterday.

In Tokyo, Jo-Wilfried Tsonga took just more than an hour to defeat Mikhail Youzhny in the final of the Japan Open. The Frenchman fired down 11 aces on his way to a 6-3, 6-3 victory that earned him a third ATP Tour title of the season.