Sir Alex Ferguson admits he was left "shocked" by Manchester United's Champions League exit against Porto.
Franciso Costinha's late equaliser put Porto through 3-2 on aggregate after Paul Scholes' header looked to have sealed United's quarter-final place.
Ferguson said: "You get shocked in life and I suppose you couldn't see that one coming. Defensively we were brilliant.
"I couldn't believe it when Scholes' second goal was ruled offside. There were three men playing him onside."
It is the first time in eight years United have failed to reach the quarter-finals of the Champions League.
Ferguson also had to contend with an injury to Cristiano Ronaldo, who was stretchered off shortly after coming on as substitute.
And Eric Djemba-Djemba was replaced at half-time with a broken rib while Mikael Silvestre did not play after suffering an ankle injury in training that could keep him out for three weeks.
Ferguson said: "Porto had a lot of possession of the ball but I felt that we were in complete control.
"It wasn't a great Manchester United performance but it was laced with a lot of good play and I think we deserved to win the match.
"Scholes' goal would have put us into a very, very comfortable position at 2-0 up, but then that's football.
"Obviously we are out of the European Cup which is disappointing having done so well and qualified for Europe so often.
"We have to ensure European football for next year but there's no reason to give up on the league - that has been proved and I don't see how anyone could have seen what happened in the last minute.
"We are in the semi-final of the FA Cup and that will not be an easy game for either side."
He said: "We have had problems defensively but we did really well in that area, but we have not reacted to the rebound and that's the first thing you have to do as a defender when the ball is going towards your goalkeeper."
Porto coach Jose Mourinho insisted he had buried the hatchet with Ferguson after some fiery exchanges between the pair in the build-up to the match.
Mourinho said: "Sir Alex said congratulations at the end and we shook hands. That's what I like in football.
"Sometimes somebody is incorrect, I have done it before and I will do it again.
"Sometimes you play with words and try and put some pressure on the opposition but when the last whistle goes it's finished, you shake hands and I'm
happy with that.
"I was also pleased to see so many Manchester United players in our dressing room afterwards changing shirts and giving congratulations, the Neville brothers
were there and some others."