IN his managerial career, Sir Alex Ferguson didn't get much wrong.

If you ask him, he'd maybe say selling Jaap Stam to Lazio in 2001, or inadvertently derailing his team's title bid by revealing his plan to quit the following year.

Ask Ally McCoist though and he'd say his biggest mistake came before.

Quite a long time before.

Rangers' greatest ever goalscorer and Scotland's finest manager go way back.

And the striking legend was the source of what he reckons is Fergie's biggest mistake.

He didn't sign him when he had the chance!

He could still identify talent when he saw it though.

Ferguson was in his second boss job at St Mirren when McCoist was an East Kilbride schoolboy and the manger lived locally so would take the teenager to training from school.

There would even be cash for a bag of chips on the way home.

But when crunch time came, the carb-loading hadn't paid off and McCoist was over-looked by the Buddies - he went on to sign for Scotland's other Saints.

And 424 goals later he still remidns Ferguson of the chance he didn't take 45 years on.

MCoist revealed: "He did [knock me back] - he said I wasn't big enough.

"And just look at the size of me now! What a poor decision that was!

"I dig him up about it every time I see him."

Speaking to Open Goal, he revealed the manager - who we exclusively revealed has recently bought a flat back in Glasgow - used to be based much closer to home.

McCoist explained: "It was a great experience - when I was 14 or 15 Sir Alex used to pick me up from the school, Hunter High in East Kilbride.

"He'd pick me up because he stayed in Greenhills in East Kilbride. It was myself and another lad Stevie Cowan who he did sign at St Mirren. He went to Aberdeen with him too.

"We'd go in and train with the S forms, then Sir Alex would take the training with the first-team and reserves and Stevie and I would wait.

"Sir Alex would give us a couple of quid and we'd nip round to the chippy in Love Street and we'd get a bag of chips and come back to wait on Sir Alex finishing

"He'd drop us off again at the house.

"That just shows you what it was like in those days.

"What a memory to have - one of if not the greatest manager we've ever produced and I can go all the way back to being picked up at school.

"Every time I see him I still dig him up about not signing but to be fair he kinda recovered from that blow quite quickly!"

And so too did McCoist.

He hit 27 goals for St Johnstone, prompting Sunderland to pay a then club record £400,000 for him.

But there were only nine on Wearside before Rangers ended his exile and so began a legendary career at Ibrox - with 355 goals and two golden boots.

He also notched 14 for Kilmarnock and 19 in a Scotland shirt before heading into media and coaching.