As European champions, United were invited to the new eight-team tournament, held in Rio de Janeiro and Sao Paulo from 5 to 14 January, in the middle of the English season.

Our participation came at a price, with Sir Alex Ferguson and his side having to forego the opportunity to defend the FA Cup, won the previous May at Wembley with victory over Newcastle United.

The decision to withdraw had been made the following month, with chairman Martin Edwards saying it was ‘in the national interest’ for United to accept the Football Association’s offer to pull out, as England were bidding to host the 2006 FIFA World Cup.

“We realise that many of our supporters will be as disappointed as we are with our decision not to compete in the FA Cup,” he said, in a club statement. “Manchester United see this as an opportunity to compete for the ultimate honour of being the very first world club champions.”

Ferguson was concerned about fixture congestion. United were coming off the back of a mammoth 1999, which had involved us playing 62 games in pursuit of six trophies, with the European Super Cup and Intercontinental Cup games added to the mix.

"We can't go for them all," he said. "We can't play in the FA Cup and in Brazil. That would be impossible.

"We're in a no-win situation here. The criticism we would have received if we hadn't gone [to Brazil] would have been unthinkable - and that's a Scotsman speaking.”

It was a hotly contested debate at the time, one which the players also had an opinion on.

“To be honest, it was something we talked about in the dressing room as much as everyone else did outside Old Trafford,” David Beckham wrote. “We were looking forward to going to Brazil, looking forward to playing clubs from all over the world. But nobody was happy about missing out on the FA Cup.

“It didn’t feel right not to defend the trophy. Perhaps we could have been given a bye through to the fourth round while we were away and joined when we came back, I don’t know. That was for the FA and the club to sort out.”

So, amid criticism from some quarters – including, bizarrely, a group of ‘celebrities’, as highlighted in an infamous Daily Mirror front page – the Reds jetted out to Rio, which was to be our base for the group stage of the tournament.

We’d been drawn in Group B, alongside North American champions Club Necaxa, of Mexico, Brazilian Copa Libertadores winners Vasco da Gama and South Melbourne, the holders of the Oceania Club Championship. The other group, played in Sao Paulo, consisted of Al-Nassr (Saudi Arabia), Corinthians (Brazil), Raja Casablanca (Morocco) and Real Madrid (Spain).

Our opening fixture pitted us against Necaxa, the game getting under way in the sapping early-evening heat at the world-famous Maracana Stadium.

United were the pre-tournament favourites, but the first 45 minutes of the tournament - in front of a 2,000-strong crowd in a 90,000 seater stadium - did not go to plan.

Cristian Montecinos bent a free-kick into the net, beyond Mark Bosnich, after a quarter of an hour, before Beckham was given his marching orders for a high challenge on Jose Milian – a decision the manager and his squad did not agree with, despite fairly damning video evidence.

“It was pathetic from the Mexican player,” said Bosnich, while Ferguson claimed the referee had bowed to Necaxa appeals.

“It was a 50/50 ball and they both had their feet in the air,” claimed the boss. “The Mexican players tried to get him sent off and the referee has reacted to that.”

The 10 men of United rallied in the second half, Bosnich saving Alex Aguinaga’s penalty before Dwight Yorke also missed from 12 yards.

Yorke made amends by steering home an equaliser in the closing minutes but, with Vasco beating South Melbourne 2-0 in the later game, we were already playing catch-up ahead of our meeting with the Rio side two days later.

Only the top team in each group could progress to the final, so we had to beat the Brazilians to stand any chance, but another nightmare first half followed – and this time there would be no Reds reprise in the Rio sunshine.

Cheered on by the local crowd, the star-studded ‘home’ side, with an attack spearheaded by Romario and Edmundo, pressured the United defence, causing the normally reliable Gary Neville to make two mistakes in the space of three minutes.

First, an errant backpass was pounced upon by Edmundo, who squared to Romario to finish, then the 1994 World Cup hero was wise to Neville’s attempted chest pass, nicking possession and rounding Raimond van der Gouw to score.

Edmundo added a third before the break, after expertly turning Mikael Silvestre, and a shellshocked United side shorn of Beckham’s creative influence couldn’t muster a second-half response, aside from Nicky Butt’s consolation goal.

“If we had come through the first half-hour with the sun I felt we would have been okay,” Sir Alex said at full-time. “Unfortunately the man who is usually the most reliable player in the club has made two mistakes which have lost it for us.”

United’s tournament was effectively over with a game to play, but, on a weekend where domestic clubs were battling the cold in the FA Cup fourth round, the Glaswegian had no regrets.

“It's been fantastic here - what a chance for us to come out and get some sun,” he told the BBC. “Back home we would have been freezing our toes off. Playing in the Maracana stadium - that's an experience that probably 90 per cent of the top players in the world don't get.

“It's been well-organised, the Brazilian people have looked after us very well. On the playing side, we wish we had been better.”

He fielded a much-changed team for the final fixture, a virtual dead rubber against South Melbourne, who were managed by a very young Ange Postecoglou in his first coaching role.

Quinton Fortune’s quickfire brace settled a tie which even the club’s official yearbook describes as having ‘an unmistakable aura of anticlimax’ about it, although it was a useful exercise for younger Reds like Jonathan Greening, Danny Higginbotham and Ronnie Wallwork, who understandably were finding first-team opportunities hard to come by at home.

Corinthians lifted the trophy four days later, prevailing on penalties over Vasco after a dull goalless draw in the final.

A second edition of the tournament was meant to be held in Spain the following year but it was eventually scrapped due to financial issues. It took until 2005 for it to return, under a new format and name – the Club World Cup.

United won that competition in 2008, but another rejig has occurred under the watch of FIFA chief Gianni Infantino and 32 clubs will descend on the United States in a bid to be crowned global champions this summer.

The prestige of the tournament, as with Brazil 2000, is still in question but what cannot be denied is that United did ultimately benefit from our spell in the South American sun, with Roy Keane likening it to a 'mid-season holiday' in his autobiography.

The Reds ended 1999 second in the Premier League and seemingly locked in a title battle with Leeds United at the halfway stage but, after a rusty return to domestic action in a 1-1 draw with Arsenal on 24 January, clicked into gear.

“I couldn’t wait to get back to some mud, wind and rain, to get on with the rest of the season,” added Beckham, recalling United’s return to England. “We might not have had the FA Cup to look forward to but, while we’d been away, no other team had been able to catch up: the Premiership was there to be won.”

As our Yorkshire rivals stuttered, we were a team renewed, winning 11 of the next 14 games and confirming another championship on 22 April, with three weeks of the season still to play out.

In a parallel universe, we'd have faced Aston Villa in the third round of the FA Cup which, for that season only, had been moved forward, to December.

Due to our absence from the competition, Darlington, knocked out in the second round, were selected as the 'lucky losers' to face Villa. John Gregory's side dealt the Quakers a second elimination and ultimately made it all the way to Wembley, losing 1-0 to Chelsea in the last final ever played at the old national stadium.

The Reds returned to the competition in 2001 but it took a few years for us to really rekindle our relationship with the famous old trophy, winning it for the 11th time in 2004 after a couple of seasons' worth of early exits.

For the record, Sir Alex later expressed his remorse at pulling out and creating a storm that still occasionally gets brought up when debating the strength of the competition, a quarter of a century on.

"It turned out to be a disaster for us," Ferguson admitted to club magazine Inside United. "We did it to help England's World Cup bid and that was the political situation.

"I regretted it because we got nothing but stick and terrible criticism for not being in the FA Cup when really, it wasn't our fault at all. The Football Association and the government felt that playing in this tournament would help England's bid to host the 2006 World Cup.

"There was a lot of undue criticism — but it was a great two-week break."