The victory of Jock Stein's Lisbon Lions over Inter Milan in the European Cup final of 1967 preceded United's defeat of Benfica at Wembley by 12 months, breaking the early dominance of the competition shared by those two clubs with Real Madrid. A subsequent record of one final appearance each . . . Celtic in defeat in 1970, United in triumph in 1999 . . . has scarcely diminished the reverence the British pair acquired on those monumental nights.

The debate over which was the greater team helped develop a bond between the clubs that has been reinforced repeatedly through meetings in testimonial games, the latest of which honoured Roy Keane in May. Yet when Celtic return to Old Trafford this Wednesday it will be their first competitive encounter. No debate will be settled now. Scottish football has declined too much for 40-year-old comparisons to be relevant. Yet the United manager, Alex Ferguson, a man in whose veins the blue blood of Rangers flows, and whose opinion of the current Celtic manager might turn the air a similar colour, demands that history be respected and insists that while United and Benfica are favourites to progress from Group F, the chances of the Scottish champions should not be dismissed.

"You cannot underestimate a team when there is a bit of history and resources behind them, " he says. "They have a chance of qualifying, there is no question of that."

He has less to say about Gordon Strachan, his strained relationship having resurfaced in the latter's recent autobiography, than about the former United player's predecessor at Celtic Park, Martin O'Neill. "They have got fantastic resources to make a challenge and they only need to look at what Martin O'Neill achieved to know what can be done. Two or three years ago they got to the Uefa Cup final, beating Blackburn and Liverpool on the way. That was a phenomenal performance. In football anything is possible. Who would have thought last year that United would not have qualified (for the knock-out stages), not even for the Uefa Cup?"

That Ferguson should emphasise his point by recalling United's experience last season, when they began as group favourites yet finished bottom, winning only one match and scoring only three goals, is indicative of the depth of hurt he felt at seeing another chance to revisit the pinnacle of 1999 slip away. This year, he says, there will be no repeat. "I would never have believed at the start of last season's campaign that we would finish bottom, " he says.

"The dividing line was that we did not score enough goals.

If we had scored one more, giving us one better result, we would have gone through.

Injuries meant that at times we had a team that lacked experience. It will be different this time, I can assure you."

United's frustrating summer in the transfer market, during which their record European goalscorer, Ruud van Nistelrooy, left and the talented but arguably unproven Michael Carrick was the only major arrival, might lead some to greet such confidence with scepticism.

But Ferguson believes such benefits as another year's experience in the legs of Cristiano Ronaldo and Wayne Rooney, plus the return to fitness of Paul Scholes, will be significant.

The last-named pair will be available after completing their controversial suspensions yesterday. "I might even pick them, " Ferguson jokes, adding, more seriously that "the 10 to 12 goals we can expect from Paul was a big loss last year".

Injuries remain an issue, with Gabriel Heinze, Nemanja Vidic and Alan Smith not fit to return. Yet United will expect to have the edge at home, even though the signings of Thomas Gravesen and Jan Vennegor of Hesselink make Celtic better equipped.