A big league player already — and into the third round of the US Open despite a few unexpected lurches — Andy Murray is about to move among the big league clothing boys as well.

It is understood that the British No 1 and world No 2 is expected to sign with adidas in the first big contract successfully concluded by 19 Entertainment, the management company he signed for at the turn of the year.

The deal would bring an end to Murray’s association with Fred Perry, which had been renewed by his previous managers on a rolling year-on-year contract and was sustained through 2009, the centenary of the birth of the last British male player to win a grand-slam tournament, 73 years ago.

Now, it is clear, Murray is moving on and into the same line that clothes David Beckham, 19’s global sporting phenomenon, and which secures the firm foothold adidas has in the tennis brand market. With Murray joining the stable that houses Novak Djokovic — the 2008 Australian Open champion and world No 4 — they are able to compete for exposure with Nike, which attires Roger Federer and Rafael Nadal.

There were times yesterday, in Murray’s 6-2, 3-6, 6-0, 6-2 victory over Paul Capdeville, the world No 87 from Chile, when he did not look himself. Indeed the legs that have become meaty pistons in recent months thanks to his strenuous strengthening efforts, did not seem to be his property at all.

It was not until an hour and 57 minutes had passed that he played a truly destructive forehand winner, right out of the sweet spot. But he came through, which is all that really matters. He will not worry about the second set, even if those watching his every stagger were a tad anxious.

It was a little warmer yesterday than the opening four days of this low humidity Open and nowhere near the hothouse conditions he has experienced in Miami, or Melbourne. But Murray had zinc smeared on his nose and, near the end of a second set in which he looked sluggish and unable to rouse himself, he chose to don a cap and drape an ice necklace across his collar, as if the sun was really bothering him. It had the effect of a 4am alarm call.

Murray whipped through the third set without dropping a game or missing a groundstroke and one break of serve in the fourth set was enough effectively to snaffle the match. Then and only then did Murray decide to unleash his full array. He will meet either Taylor Dent, of the US, or Ivan Navarro, the Spaniard, in the last 32.

Before Murray stepped out, he had plenty to live up to. Those top-ten players in the top half of the draw who had played twice — Federer, Djokovic, Andy Roddick, Nikolay Davydenko and Fernando Verdasco — did so without dropping a set; neither had those in the bottom half after one round. The stars are on a nice roll.

It helps, perhaps, if you can set your watch to an appointed start time. It was not supposed to work out that way but Roddick has become the night-bird of the event, twice having to start at 11.15 in the evening.

The Wimbledon runner-up defeated Marc Giquel, of France, 6-1, 6-4, 6-4 and now plays John Isner, his fellow American who is suitably at home in the city, as he stands 6ft 9in.

• Comments about Dan Evans, the British tennis player, were wrongly attributed to Colin Fleming in our report (Davis Cup ban has Brown and LTA poles apart, September 4). We wish to make it clear that Fleming, who made his Davis Cup debut against Ukraine last month, has never said anything about his fellow player in this context and we are happy to set the record straight.