Alex Ferguson and the rest of the 30-plus Manchester United party arrived in sweltering Brazil yesterday morning with three Cs at the front of their collective thoughts: culture, climate and credibility are United's causes for concern - only Jaap Stam mentioned the possibility of kidnapping.

The three represent serious challenges to United's twin tasks in Rio de Janeiro over the next 12 days, which are to win the inaugural World Club Championship while simultaneously convincing a sceptical domestic audience that it is worth winning in the first place. Failure to do one without the other could render the venture a wasted enterprise.

Because at the first sign of any of the matches involving the eight teams looking either substandard or like an exhibition game - and questions are bound to be raised when Raja Casablanca of Morocco meet Saudi Arabia's AlNassr on Friday night in Sao Paulo - English derision will again focus on United's participation in Brazil at the expense of defending their FA Cup trophy.

They are hardly unused to being the object of people's anger down Sir Matt Busby Way, but, with the bulk of the FA Cup fourth round to be played this Saturday, it means that United's potentially most interesting and exciting fixture, also on Saturday, against a Vasco da Gama side including Romario and Edmundo, may suffer from "the lack of projection" Ferguson said has "made it hard to get enthusiastic" about the tournament as a whole.

Ferguson has spent the past few days doing his bit to talk up the competition - and to justify United's presence in it in the process - and his concentration has been on the fact that FIFA, whose brainchild it is, would not dare let it fail.

For his own personal prestige, and for increasing the organisation's already overbearing influence on the world game, FIFA president Sepp Blatter will demand successful logistics at least. This event must be made to look credible. Yet the most pertinent remark Blatter has made in the past few days has been: "First, we should be able to watch some attractive football. Second, club football is new - and lucrative - territory for FIFA." Blatter probably goes to sleep watching banknotes jump over fences, sponsored fences, of course.

But the FIFA bean-counters must be reasonably happy so far. Around 1,000 journalists are expected in Brazil to report on the games, thus guaranteeing global coverage, while television rights' sales have been brisk and profitable. The BBC alone is reckoned to have invested some Stg£2 million in securing exclusive television and radio rights.

What spectacle they will broadcast, however, brings us back to Ferguson's concerns about climate. "Most of our players have played in heat before," Ferguson said before departure, "maybe a blazing hot day in August. But this is a prolonged spell of playing games three or four days apart in heat of 30 degrees. The pitches will be rock hard, so it will be completely new to us. We'll have to find a way of coming to terms with that.

"But we've watched videos of Brazilian games played last January and a lot of it is at walking pace with little bursts. I think the important thing is there is an incentive here, it may be hard work for the players but the incentive is to get to the final and win it. Then you're coming back with the world championship trophy - it's got to be worthwhile."

It sounds straightforward when put like that but Ferguson knows from the recent Intercontinental Cup match against Palmeiras in Tokyo that the Brazilians approach these kind of occasions with rather more intent than European sides have done traditionally.

"It was a terrific match," he said of Tokyo. "I think you can go to these games and we've seen in the past that the South Americans can be a bit cynical about it. But the Brazilian culture seems to be a bit different, they try to win all the time. I think you are a victim of your own culture and history, but I was surprisingly refreshed by their attitude."

At the age of 35 Romario's rushed return to his first club, Vasco, is evidence of Brazilian determination. He even thinks the tournament could be as important as the World Cup. But then Romario has never played in an FA Cup.