Nobody was expecting Walsall - under Jan Sorensen - to win the game, but goalkeeper Jimmy Walker and tricky winger John Hodge were determined to outfox United.
United's starting line up on the day in front of a crowd of nearly 55,000 included David Beckham, Paul Scholes, Gary Neville Peter Schmeichel, Dennis Irwin, Andy Cole and Ole Gunnar Solskjær Daunted by it? Not Walker, who was more concerned about getting a decent night's sleep prior to the showdown with The Reds.
He said: "My room mate on away trips was John Hodge who never seemed to want to sleep - you were never guaranteed a good eight hours with Hodgy, quite the opposite. "Mind you the hotel we stayed at was a top class venue in Cheshire, more like a stately home and the beds and facilities were fantastic. "As usual Hodgy couldn't stop still and he noticed all these stuffed animals on the walls around the hotel corridors. He must have been thinking about it all night because after the obligatory few hours sleep I woke up early and he said to me: 'We've got to get that fox that's outside the room and take it to Old Trafford as a mascot.' "He started trying to take it down and I said 'we'll never get it out of here.' I went down to reception and told them what we were planning and to be fair to them they were great - they said we could take it if we brought it back and mentioned them in any post match interviews.
"So the fox went with us to the pre-match lunch, on the team coach to Old Trafford and we took it in the dressing room where it was a talking point"
As expected, United were too strong for Walsall that day in winning 5-1, both Cole and Solskjaer getting two goals each but Walsall had their own fox in the box that day in Roger Boli.
Boli, a gem of a Sorenson signing who had spent most of his career in the top French league, scored a goal from a looping header to reduce the deficit at 4-0 after a cross from compatriot, Jeff Peron.
Walker said: "We had all agreed if we did manage to get a goal our celebrations would be to fall to the floor as though we had fainted which I did but I seemed to be the only one.
"Roger and Jeff went to the corner flag to celebrate - I think some of the fans must have thought I really had flaked out. "It was a great day though because the way Jan set us up, he gave us the freedom to play, even against a side like United and it was better than just defending for 90 minutes - though I remember I had to make some decent saves but if you look at their line up no wonder."
"In the second round we had absolutely destroyed Macclesfield 7-0 away - Jeff (Peron) must have set up six of them. I don't know how Jan got players of that quality but he assembled a great squad who seemed to turn out for the big games. "The Peterborough game in the third round had been postponed but the draw for the fourth round already made and I remember knocking on the chairman's door and asking him what the chances were of a post season trip abroad if we beat them and played United - it paid off as we all went to Ayia Napa." Walker's love affair with the competition continued as he made a double save against West Ham in the third round in 2001 which was voted the best of that season.
He made 13 appearances in five years at The Hammers and later coached at the club until he got his current role as assistant to Paul Konchesky for West Ham United Women in the WSL.
On the Leicester game in the next round he said: "It's a great tie for Walsall or any side in League Two and all the more deserved as you have to work extra hard at that level to get there. It will be a great occasion and I think Walsall will have a chance."
Starting line ups on January 24 1998
Manchester United (4-4-2): Schmeichel; Irwin; Berg; Johnsen;P Neville; Beckham; McClair; Scholes; Thornley; Cole; Solskjaer. Substitutes not used: G Neville, Giggs.
Walsall (4-4-2): Walker; Evans, Mountfield; Viveash; Marsh; Watson, Keates, Porter, Peron; Hodge, Boli.
Attendance – 54,669