The first half was as good as it gets. We led 3-0 and United's all stars - Beckham, Scholes, Veron, van Nistelrooy and Cole all started - were left scratching their heads.
But the second half was a complete contrast. The United we all know turned up and all the belief gained from leading 3-0 at half-time against the champions visibly drained out of us.
Five goals followed in a display few will forget.
So much happened in 90 minutes that it is perhaps better just to stick with the basics.
Dean Richards, making his debut, had the dream start when he flicked home Christian Ziege's wicked corner after 14 minutes.
It took just 11 minutes for us to double the score. United had successfully played an offside trap but on this occasion Poyet's delightful chipped ball found Ferdinand onside. The striker took a second to take the ball out of his feet, steadied himself and buried a low drive into the bottom corner.
United looked shellshocked and after a trademark Beckham free-kick was saved by Sullivan, their problems increased with the loss of Butt with what appeared to be a rib problem.
Solskjaer came on but it was 3-0 before United could settle. And this was a goal to remember.
We kept the ball for what seemed an eternity - so long, in fact, that the crowd started to sing 'ole' with every touch - when Taricco played Poyet down the left, he had time to control the pass and turn onto his left foot before picking out Ziege at the far post with a wonderful cross, met with a diving header for a 3-0 half-time lead.
Everyone knew United would come out fired up but few could have guessed what was to follow.
They came out with intent etched all over their faces and it took just a minute for them to hit back as Andy Cole headed home Neville's near post cross.
Beckham went close with another free-kick before second goal after 57 minutes.
The England skipper was involved again, floating in a corner met plum by Blanc's forehead from 10 yards for 3-2.
Suddenly there was an air of inevitability around the Lane as United came forward in waves.
Johnsen headed Beckham's corner wide after 66 minutes but it was soon 3-3 as Silvestre, on as a second half substitute for Irwin, crossed superbly for van Nistelrooy to head home from 10 yards.
Five minutes later and they were ahead, a delightful move ending with Solsjaer's flick into Veron who shot into the corner from 15 yards.
Sullivan saved well from van Nistelrooy but the fifth goal was always a possibility and arrived Beckham, a classic drive from the edge of the box, with four minutes left.
The emotions couldn't have been different at the final whistle but as they always say, the best always hit back hard when the chips are down.
Glenn Hoddle suggested in his press conference on Thursday that 'even if you are 3-1 up against United with 20 minutes left, the game still isn't won'. How right he was.