Celtic goalkeeper Artur Boruc revealed how memory served him well as he saved Louis Saha's late penalty to book his side a place in the Champions League knock-out stages for the first time.
Manchester United striker Saha was denied from the spot by Boruc with barely a minute of regulation time still to play.
The Parkhead side had been second best for most of the match but took a sensational lead nine minutes from the end when midfielder Shunsuke Nakamura's stunning free-kick from 25 yards sailed past Edwin van der Sar.
As Celtic Park rocked, there were two more moments of drama to come, a missed sitter by United striker Saha and the Frenchman's penalty.
Poland international Boruc took heed of the way Saha shot when he scored from the spot in United's 3-2 win over Celtic at Old Trafford in September - and went the correct way, diving to his right to palm away a firm strike.
Boruc said: 'I don't know about it being a great save from the penalty. Every time a keeper saves a penalty it is luck, that's all.
'I was thinking about the last penalty he scored against me and I thought he might do the same thing. That's what was on my mind.
'We were celebrating in the dressing room when someone came in with news that we had qualified and so there was a double celebration.'
With one game remaining in Group F, Celtic have nine points and cannot be stopped from entering the last 16 by either United or Benfica, who play each other next at Old Trafford.
Despite Celtic creating club history, manager Gordon Strachan played down suggestions that the achievement was the pinnacle of his managerial career to date.
He said: 'I think it's unfair on the players and people that I have worked with over the years. It would be disrespectful to them. You just thank the players for a night like this.
'I have been lucky to play with some great players in my career but last night I was lucky to have good players who helped me as a manager. And I had that at Coventry and Southampton as well, when I was manager there.'
However, Strachan did offer special praise for his two heroes, Nakamura and Boruc.
He said: 'At the free-kick you have somebody who is as good as anybody in the world at them, and then you have a goalkeeper who can pull off saves like that.'
