It was 25 February 2004 at the Estádio do Dragão, and a fractious Champions League tie ended with Manchester United defeated and their manager condemned for refusing Mourinho's hand after the final whistle. A myth. Ferguson did shake his adversary's hand that night. It was a split-second later when he raised a finger towards Mourinho's face and, body shaking, voiced his opinion on a Porto performance spiced with theatrics.
Nine years on, and before they meet again in another last 16 tie on Wednesday, the pair are more likely to take tea together – as they did in Manchester's Lowry Hotel before Real Madrid's draw at Manchester City in November – than rebuke or provoke each other. It is a most unlikely friendship, competitively, tactically, socially and allegedly politically, but particularly when one considers the rancour of that first date in Porto.
The United manager was incensed at Vítor Baía's part in a late red card for Roy Keane, overlooking how the United captain had used the Porto goalkeeper as a springboard. Mourinho perpetuated the handshake myth and ridiculed the man he now calls "Boss". "I understand why he is a bit emotional," he said. "You would be sad if your team gets as clearly dominated by opponents who have been built on 10% of the budget."
It takes a Special One to come back from that with Ferguson, especially when one considers Rafael Benítez's observation that "when I became Ferguson's rival we were no longer friends". Two weeks later came the sight of Mourinho haring down the touchline at Old Trafford in celebration of the 90th-minute Costinha goal that sent Porto through.
Now, Ferguson is looking forward to the prospect of facing his friend and rival at the Bernabéu. "I think he'll relish going up against me," he laughs. "It's a great challenge, the two biggest clubs in the world. It's a great game for us. They got a bad start in the league and they're chasing their tails because Barcelona's form is incredible. So I think José has set his sights on the European Cup this year, no doubt about that. It makes it harder for us in one way, but for them, too."
United's record against teams managed by Mourinho does not bode well for Ferguson, although he does have home advantage for the second leg. He has won three of 14 games against Mourinho's Porto, Chelsea or Inter (including a penalty shootout in the 2007 Community Shield) and lost six.
In a documentary on Mourinho last year Ferguson claimed the 50-year-old is not the "cocky bastard" who swaggered into Stamford Bridge in 2004 and self-deprecation is one reason they get along. "When he comes into my office he can take a joke against himself, that is what I like about him," the United manager said. "I give him a lot of stick and he laughs it off." And, of course, they are both obsessed with winning. They may employ different methods, Mourinho the arch-strategist against Ferguson the risk-taker, but they share the same goals. Both of them this season are chasing a third Champions League winners' medal.
Mourinho will become the first man to win the Champions League with three different clubs should he lead Real to a 10th victory in what is expected to be his final season in Madrid. "I think the European Cup has always been important to him," Ferguson says. "He's done a great job there, he's got a terrific squad, so I don't think that [threat to his job] applies. But you never know in football. But there's no secret about his desire to win the European Cup. He'd be the only person to win the European Cup with three different teams, so it's a fantastic challenge for him."
It is also a motivation for Ferguson to emulate Bob Paisley's hat-trick of European Cup wins with one club. "Of course that interests me," he says. "I keep saying this club should have won more European Cups. On a few occasions we've been very unlucky. It's an opportunity to get to Wembley again and do better."
Mourinho may view the tie as an audition for the United job when Ferguson retires – unless his insatiable drive means Mourinho has to retire first. The Portuguese's methods, style of play and tendency to upset his employers do not appear a natural fit for Old Trafford, though Ferguson believes his potential successor has adapted to the traditions of Real from the conservatism of Chelsea and Inter.
"That is something where maybe you have had a change [in Mourinho]," he said. "He's got Ronaldo, Di María, Benzema, players like that. Before that you had the galácticos when [Florentino] Peréz first became president. In that spell he had Figo, Zidane, Roberto Carlos, Raúl. But I don't think any of those players were as good as [Cristiano] Ronaldo. I really don't. Zidane was a fantastic player, Figo was a fantastic player, but not as good as Ronaldo. So I think he is still living up to the reputation that Real Madrid can produce the top players."
As Ronaldo prepares to face his former club for the first time as a Real player, Ferguson is proud, not fearful, of the improvement the player has shown since he left United in 2009. "He's beaten all the records there," he says. "He's beaten Di Stefano, Puskas, Hugo Sánchez, all their records. He is indelibly printed in their history now. Ronaldo is pivotal to everything they do. I knew he would improve tremendously as he was still young when he left us. It was obvious he was going to be the top player in the world, there was no doubt about that."
The world record £80m transfer fee will be no consolation should Ronaldo interfere with United's Champions League ambitions for another year. "We should have asked for £150m," Ferguson says. "We probably would have got it."