He admitted the pain will cause a few sleepless nights and will haunt his team-mates for years to come.

But, even though United trail Arsenal by nine points in the title race and must overcome the imperious Gunners in the FA Cup at Villa Park next month if they are to stand a realistic chance of landing any silverware this term, Neville rejected any suggestion their era of dominance is over.

He is already spying the chance to salvage some battered reputations in Sunday’s Manchester derby at Eastlands and insisted Alex Ferguson’s side will bounce back.

“You can kill yourself with frustration looking back to try and find where things went wrong, so you have to accept the situation and deal with it,” said the 29-year-old defender.

“We know people will look at the result and say it’s been a disastrous season for Manchester United but we can’t let that affect us.

“Seven weeks ago there was a team in England who were clear in the Premiership and had the best defensive record in the league. That team was Manchester United. Suddenly we are a shambles.

“It’s going to be difficult to pick ourselves up from this. We’re not talking about three or four days, it’s more like three or four years. But we owe it to ourselves and the fans not to feel sorry for ourselves.

“We have a huge game on Sunday and we cannot afford to go into it with anything other than a positive attitude.”

Having been part of the United side that scored two injury-time goals to snatch the 1999 Champions League final from Bayern Munich’s grasp, Neville now knows what it feels like to be on the other end of the result.

“It was a real kick in the teeth,” he said.

“We were two minutes away from walking away with our heads held high and ended up feeling shell-shocked.

“No-one can deny it is a massive blow to our season and everyone is very deflated.”

What made it even more galling was that even without suspended pair Rio Ferdinand and Roy Keane, plus injury victims Mikael Silvestre and Quinton Fortune, the Red Devils had turned in their best defensive performance in weeks.

Had it not been for an incorrect offside flag that prevented Paul Scholes from putting his side two ahead just before the break, United would probably be looking forward to their eighth successive quarter-final appearance.

As it is, Neville is left scratching round for the reasons behind the failure.

“Rio Ferdinand’s suspension is a factor but you should be able to cope with things like that,” he said.

“What you can’t legislate for is losing so many players in the same position at exactly the same time. I realise some of the damage is self-inflicted but it’s a reason.

“There were other factors too, not least of which was that we didn’t perform in the first leg and as players we have to take responsibility for that.

“I don’t think we could have defended any better than we did last night no matter who was available but we never had control of the match the way you would expect Manchester United to have at this stage of the competition.

“We expect to dominate the opposition. Having got one goal, we usually push on and try to get a second or a third.

“Yet because of the way we have been defending recently, we didn’t have the confidence to do that.

“It sounds like a list of excuses but it’s not meant like that. Porto are not a better team than us but they deserved to go through because they got the goals when it really mattered.”

The fall-out is not restricted to finance and lost pride either.

After an outstanding performance at the heart of United’s defence, Neville must now step aside for the remaining two games of his domestic ban.

Ferguson has also confirmed Silvestre will be out for at least two weeks with his knee ligament injury, while Fortune is likely to be sidelined for a similar length of time following his cartilage operation.

If that wasn’t bad enough, Eric Djemba-Djemba has broken a rib while the sight of Cristiano Ronaldo limping heavily as he left the ground last night does not bode well for the young winger’s chances of being involved for the next few weeks either.

It leaves Ferguson to play a numbers game ahead of the trip to face a City side whose league position leaves them urgently requiring victory even without added incentive of heaping more misery on their neighbours.

“Our season is not over,” said Neville. “We have a lot of big games to play yet, not least of which is Sunday.

“We have to keep working hard and in the end the situation will turn.”