It cost the Rangers manager pounds 40m to build his team, the exception to the largesse being the former Leeds United striker. Yet Wallace has proved the most priceless of all. His 49th-minute piece of larceny, which condemned Celtic to an empty season, was his 29th goal of the campaign and, as the one which sealed the treble, may be the best remembered by Rangers fans.
The showpiece occasion, which was returning to Scottish football's spiritual home after an absence of three years and pounds 65m spent on Hampden, passed off without the kind of trouble which marred the last meeting of the Old Firm. Yet, it is doubtful if the Celtic supporters noticed any of the improvements as they trooped away at the end.
The Celtic players were disconsolate at the end. Paul Lambert lay prostrate on the turf, grieving over the controversial 88th minute incident when referee Hugh Dallas failed to award a penalty after Lambert's shot appeared to strike Lorenzo Amoruso on the arm.
The overwhelming focus prior to the match had been on the potential for trouble on and off the pitch, that it was almost as if football had been forgotten.
The man most under pressure was referee Dallas, who was in charge of that last troubled occasion, and if he sought anonymity this time, then he was to be disappointed.
An opening 20 minutes laced with tension and late tackles, meant that the Fifa referee was forced to imprint his authority. The first test came after just four minutes when Regi Blinker went down in the Rangers box but his penalty claim was rightly ignored.
Twelve minutes later though, Dallas was fishing out the first yellow card of the day. Few could argue with it, certainly not Celtic defender Johan Mjallby, who chopped down McCann after the Rangers winger had skipped past the Swede. The free-kick was in a dangerous position, but Jorg Albertz fired high over the bar.
Albertz's slackness almost proved more costly in the 21st minute after his miskick led to Paul Lambert being presented with a chance to volley the ball just outside the area but his ferocious left-foot shot crashed off the crossbar with Rangers' goalkeeper Stefan Klos beaten.
Imperceptibly though, the tide of Celtic pressure turned as Rangers launched their own attacks. Wallace got the clearest sight of goal, in the 27th minute, after Derek McInnes released the former Leeds United forward from the clutches of his marker, Enrico Annoni, but Jonathan Gould saved bravely at Wallace's feet. The Celtic goalkeeper then pinched the ball off Gabriel Amato's toe after another piece of McCann magic.
Celtic's man-marking tactics worked well in the first-half, but within four minutes of the second the good work was undone when Wallace was left unattended inside the six-yard box to plunder the opening goal.
A marauding run down the left flank by wing-back Tony Vidmar ended with a fine delivery into the box. McCann poked a foot at the ball ahead of Stubbs, and it perhaps fortuitously spun into the path of Wallace who coolly rifled his shot past the exposed Gould.
Celtic were stung, but it was not until after the hour mark that they threatened to score. Blinker found Morten Wieghorst with a delicate cross and the Dane brought it down before thundering a right-foot shot which Klos parried wide.
Blinker was then booked for a dreadful challenge on McInnes before Stubbs provided a more legitimate form of menace with two volleys after Colin Hendry had headed out Lubomir Moravcik's cross. The first floored the Rangers defender, and then the rebound required Klos to make a crucial save.
The bad news for Celtic is that Advocaat will be around to haunt them for longer than they thought. The Rangers coach revealed after the match that he has extended his contract until 2002.
"I agreed an extra two-year contract," he said, "which gives me three years to do the job I want with Rangers. I have to add to the squad to compete properly in the Champions' League. You cannot expect to do everything in one season."
Domestically, though, that is exactly what Advocaat's players have done securing their first treble since 1993 and only the sixth in the club's history.