Between 5pm and midnight on January 31, 2007, Gers boss Walter Smith made repeated attempts to lure McDonald to Ibrox for a little under £400,000.
Five months later, with McDonald's contract winding down, Celtic snapped up an unbearably restless striker for £700,000.
As Rangers struggle to find the goals which would secure a £12m Champions League bounty, the quibbles over the extra £300,000 which might have sealed a deal now look horrendously costly.
"Wattie phoned me up at 5pm on the 31st and asked if they could get Scott," recalled former Well boss Malpas to the Daily Mail. "I said no, but I had to take it to the directors.
"I spent two hours on the phone to him that night trying to pacify him. All he saw was the big money, the big club and his big chance. I then had to go into the ground the next day to calm him down further. Thankfully, he was beginning to see things from both sides by then.
"He knew he still had a job to do for the club and we made him realise the offer just wasn't good enough. Wattie was trying to get him because he needed a goalscorer, pure and simple. It made sense because, in my opinion, he was also one of the few managers who could handle Scottie's moods better than anyone else."
Malpas also remarked: "I think everybody knew Scott would score goals.
"He has his faults but Gordon seems to be succeeding in ironing those out.
"When you play for Celtic or Rangers, you have more opportunities to score. We always thought Scott would be a 20-goal-plus player for Celtic, but I didn't think he would reach 30. Maybe his mentality has changed now because he is at a bigger club. That selfishness and mumping was part of his nature, but Terry Butcher and I tried to tone it down. There is nothing worse than a player who thinks he runs the show.
"Scottie used to get upset at the slightest thing, but he is learning that it's not all about him - he has to think of the team first and foremost."
That particular penny appeared to drop in the aftermath of Rangers being rebuffed early last year. When Celtic came in, £700,000 was a premium to pay for a player entering the last year of his contract. Recent evidence backs up the belief of Malpas, however, that the Parkhead club secured a promising 23-year-old for a song.
"There was never a plan to keep him until the end of his contract," he said. "With all respect to Motherwell, Scott never really wanted to be there - he wanted away to a bigger club. But no one thought that would be one of the Old Firm.
"When he came to us, he was overweight, moody and grumpy. We sorted out the weight issue at least. Celtic came in with a deal which was right for the club.
"The timing was wrong and Celtic were a bit naughty. They came in before the end of the season with a take-it- or-leave-it offer and that left a sour taste in my mouth. But there were no other clubs who would have paid us what Celtic paid for him."