There he had been notorious for his "Polo" formation, so christened because there was a hole in the midfield. Last night he strung five players across the centre and, when United had the ball, pulled all but a lone striker into defence.
The result was a slow-paced, cagey match until the last 15 minutes when a previously lethargic United, at last stirred by the prospect of dropping two points, produced one of their famous late rallies.
It almost paid off, with both Dwight Yorke and Henning Berg going close before, in the dying seconds, it seemed as if Old Trafford was going to see a reprise of last season's greatest moment, a second viewing of the Red Devils' fabled finish for all those supporters who had not made it to Barcelona.
But then Teddy Sheringham, the man whose injury-time equaliser had set up their Champions' League triumph, failed to score as the goal gaped before him. From supersub to mortal in three quick months.
United now go to Austria - to play Sturm Graz, who lost to Marseilles last night - needing a victory to put themselves back into the box seat in Group D.
"They will be looking for a result having lost and that should suit us," said Sir Alex Ferguson of United's next challenge. "This is not a bad result for us. It's not the worst result.
"You don't always have to play at 100 miles per hour but there are moments when you have to increase the pace and we didn't do that in the first half. We improved a bit in the second half, quickened our play, showed more imagination and created more. Teddy might have won it, it was unlucky."
"I got our tactics right," said Ardiles with a quiet smile. "We knew we had to control the midfield." It may not be pretty - of the 16 clubs in the competition last night his were the only ones not to register a shot on target - but it might keep him in a job.
It helped his cause that United were a shadow of the side which romped through Europe last spring. Only four of the men who had danced off the Nou Camp as champions of Europe had survived the intervening 110 days: Jaap Stam; David Beckham; Ryan Giggs; and Dwight Yorke. Not all the changes were enforced but, with 11 players injured or ineligible, United did have an unfamiliar appearance.
Yet, while Ferguson had to give both Michael Clegg, at right-back, and Mark Wilson, in central midfield, their first European starts the substitutes' bench, which featured five internationals, underlined United's strength in depth.
The display on the pitch, however, offered another view. United lacked the drive and intensity which usually marks their European adventures and while it may have been a sense of anti-climax, that they just had to turn up to win, it may also have been due to the absence of Roy Keane.
Like Zagreb, they failed to put a shot on target in the first period, eventually stirring eight minutes into the second period when Giggs brought Drazen Ladic to his knees with a low shot. Old Trafford, which had been quietly dozing off, apart from the bare-chested Croatian support, jerked awake. A few minutes later Wilson also tested Ladic but there was still a lethargy about United and, just before the hour, Sheringham was brought on.
At last the tempo rose and Andy Cole, turning Mario Tokic, thumped a shot at Ladic which the goalkeeper pushed away for a corner. From this Stam headed wide. As the pressure rose Edin Mujcin was booked for fouling Beckham, whose deflected free-kick was grasped on the line by Ladic. Then Henning Berg, supplementing the attack, dived to head narrowly wide from Paul Scholes's cross.
By now 50,000 voices were appealing for every corner; every clearance brought a groan. United moved closer with Yorke hitting the bar from a difficult angle but the goal was not to come, not even when Sheringham was pulling the trigger. Using his right foot instead of his better positioned left, he struck the goalkeeper's boot.
Perhaps it was fitting. Last year's triumph was a seat-of-the-pants affair from the first Champions' League match, a 3-3 draw with Barcelona, to the last. So hold on to your remote controls, United are on the road again, alternately scrambling and marching across Europe.
Manchester United (4-4-2): Van der Gouw; Clegg (Fortune, 74), Berg, Stam, Neville P; Beckham, Wilson (Sheringham, 59), Scholes, Giggs; Cole, Yorke. Substitutes not used: Bosnich (gk), Irwin, Curtis, Cruyff, Greening.
Croatia Zagreb (3-5-2): Ladic; Tokic, Juric, Tomas; Saric, Biscan, Jurcic, Mujcin (Mumlek, 69), Cvitanovic; Rukavina (Sokota, 88), Simic (Mikic, 66). Substitutes not used: Vasilj (gk), Sedloski, Sabic, Jelicic.
Referee: N Levnikov (Russia).
Results, page 27