It appeared that his side were heading out of that season's Champions League, but Costinha's late winner sent Manchester United packing as Mourinho scampered down the touchline to join in the celebrations with his players.
The Portuguese club returned to the scene, albeit without the self-proclaimed 'Special One' in their dugout, five years ago today when the two teams were paired together in the quarter-finals of the same tournament.
© Getty Images
Many had tipped holders United to advance through to the last four with relative ease, but they were sluggish from the first whistle, which the visitors seemed determined to prosper from.
They did just that with four minutes on the clock when Jonny Evans failed to fully clear Lucho Gonzalez's cross from the right flank. The ball dropped kindly for Cristian Rodriguez, who cut inside United's Northern Irish defender before slotting the ball out of Edwin van der Sar's reach.
An error up the other end, though, meant that Porto's lead lasted for just 11 minutes. Centre-back Bruno Alves attempted to pass the ball back to his goalkeeper Helton, but he did so without looking. Consequently, an alert Wayne Rooney capitalised to inherit possession and then lift the ball over the stranded Porto custodian.
© Getty Images
Rather than spark an onslaught from the home team, it was Porto who continued to carve out the better opportunities as the half wore on, but neither Rodriguez nor Hulk were able to convert their more than presentable openings.
It was a similar story after the restart, with Raul Meireles and Lisandro Lopez both calling Van der Sar into action, much to the disapproval of the home support, who were demanding the introduction of Carlos Tevez from the bench.
Sir Alex Ferguson granted them their wish in the 72nd minute as the Argentine entered the action and it would take him only 13 minutes to have an impact on proceedings. He gambled on Rooney's acrobatic flick on at the near post, which afforded him enough space to send the ball into the roof of the net.
However, with 60 seconds of normal time left to play, Porto claimed the dramatic equaliser that their performance had warranted. Lucho crossed to the back post, where an unmarked Mariano Gonzalez was waiting to divert the ball into the net as Van der Sar swiftly approached.
© Getty Images
"Given the importance of the game it was a terrible goal to lose and we've only ourselves to blame. I think it exemplifies the fragile nature of our defence at the moment," Ferguson told reporters after the final whistle.
Meanwhile, looking ahead to the second leg in Portugal, the Scot added: "It's a difficult job now. It's not made any better when they tell you that no British team has won in Porto, so we have a job to do. We have to think that the last goal we've lost tonight is one we couldn't afford to lose, it was a terrible goal to lose"
MAN UNITED: Van der Sar; O'Shea, Vidic, Evans (Neville), Evra; Fletcher, Carrick, Scholes (Tevez 72), Park (Giggs); Ronaldo, Rooney
PORTO: Helton; Sapunaru, Rolando, Alves, Cissokho; L Gonzalez, Fernando, Meireles (Costa) Rodriguez (M Gonzalez); Lopez, Hulk