Sir Alex Ferguson and Arsene Wenger went head-to-head for the biggest honours in the game during a memorable managerial duel following the Frenchman's arrival in England in October 1996.
Victory over Arsenal in the FA Cup semi-final replay at Villa Park triggered United's run to the treble, with Giggs netting arguably the most important goal with a fine dash through the entire North Londoners' defence.
The normally calm and considered Giggs admits he had to adopt an entirely different persona when faced with Wenger's side and had a particular hatred for four opposition players - including some members of The Invincibles squad.
"I didn’t like Arsenal," Giggs told the Daily Mail. "I didn’t like Vieira ’cos he was dirty and got away with murder. I didn’t like Petit because he had long hair. I didn’t like Bergkamp.
"I didn’t like Pires even though when you meet him now he’s actually dead nice. I wouldn’t even look at them, didn’t know them and didn’t want to. I wouldn’t allow myself to rate any of them.
"Bergkamp? Nah, I told myself he wasn’t as good as Eric Cantona. I wasn’t really that kind of person.
"It wasn’t really me. But you had to get that in your head, that intense dislike. It was pure motivation.
"But deep down we knew. They were top drawer and that rivalry was everything to us. Deeper even than Liverpool at that time."
Though the '99 final against Bayern remains one of Giggs's finest achievements as a professional, it was a largely frustrating night for the winger who started the game out of position on the right.
Roy Keane and Paul Scholes's suspension forced Ferguson into a reshuffle, with David Beckham moved centrally and Jesper Blomqvist deployed in Giggs's favoured position on the left.
Despite a frustrating evening until Teddy Sheringham and Ole Gunnar Solskjaer's late goals the current Wales manager maintains he always believed a comeback was possible.
"There is a bit of me — and I don’t think I have said this before — that felt I should have been playing centre mid," he added.
"It was between me and Becks and I felt I could have affected it more. I was a little bit, 'I am in the wrong position here'. But that’s no excuse. We knew we could make history or fail and with 10 minutes to go I just thought it was gone. Nightmare.
"I always used to say that we would get one chance but in that one we were that bad there was just nothing. I was definitely drifting off a little bit in my mind. I knew I would have to face my mates and I wondered if I would ever be there again."