The St Johnstone striker was a raw 20-year-old when he sat on the bench for Rangers at the 2003 final against Dundee. At one point, then-manager Alex McLeish told him he was going on, but an injury forced a change of plan. Still, after Lorenzo Amoruso struck the only goal of the game, in the 66th minute, MacLean was officially part of the winning side.
The experience has only strengthened his determination to get his hands on the old trophy by more conventional means. Signing on at St Johnstone, a club with an historic distaste for silverware of any sort, might not have seemed the best way of going about it, but the Perth outfit, who meet Aberdeen in the cup semi-final at Ibrox next Sunday, are now tantalising close to helping the striker fulfil his dream.
In which light, this win, far more comfortable than the scoreline suggests, was a satisfying warm-up for the men from MacDiarmid Park. It tested their mettle, as they had to overcome the setback of falling behind after just four minutes, and it also tested their legs as the heavy pitch sapped energy away. Long before the end, though, it appeared that Kilmarnock were far more drained by their exertions than St Johnstone were by theirs.
Just to make things easier still, MacLean and fellow striker Stevie May passed the scoring chores over to central defenders Frazer Wright and Steven Anderson, whose first-half goals put St Johnstone in a position of command that they never really looked like losing. Wright struck brilliantly with his head in the 30th minute when he turned a Lee Croft corner in at the near post, while Anderson's deft flick, also from a corner, 13 minutes later accounted for the second.
Anderson's testimonial year has just begun, and MacLean came up with the mischievous suggestion that it might just be having a bearing on his recent sharpness in front of goal.
"I thought we would be dangerous from set plays," said MacLean. "Whoever scores the goals, or however we get them, we'll be happy. We created a few more chances and we could have got more goals.
"I said earlier in the season that Ando hadn't scored many, but he seems to have got a few recently. It must be the testimonial. He must be buzzing for getting that cash."
For his part, MacLean is buzzing for getting back to Ibrox. "It's a great place to play football," he smiled. "I'm really looking forward to it and hopefully we can bring a few fans with us and Aberdeen will bring a few as well. It would be good to keep them quiet."
MacLean missed St Johnstone's 4-0 Scottish League Cup semi-final loss to Aberdeen at Tynecastle in February while he was recovering from knee surgery, but he felt more scarred by that than by the surgical knife he had just been under. The scoreline flattered Aberdeen that day, and MacLean suggested his side will have added motivation as a result.
"I wouldn't say we owe them one, but we owe ourselves one for that day," he said. "People say it wasn't a 4-0, but it was a 4-0 and we have to put that right. If we play anything like we can do then we are a match for any team in the Premiership. We'll just be concentrating on our own performance and with a bit of luck along the way we can get to that final."
Yet while St Johnstone and MacLean are now in onwards-and-upwards mode, this result left Kilmarnock contemplating the possible precipice of involvement in a relegation play-off. As their disconsolate supporters filed out of the Rugby Park stands, their woes were deepened by news of the two late goals with which St Mirren had secured their 3-2 home win against Motherwell.
At least their players seemed to be sharing the pain. Aside from Robbie Muirhead's fourth-minute goal - the 18-year-old struck after St Johnstone goalkeeper Alan Mannus had parried a shot by Kris Boyd - the most animated effort by any of the home players was Alexei Eremenko's angry swipe at an advertising board when he was substituted in the 77th minute.