The Rangers forward had endured a difficult start to the campaign and was roundly criticised for his profligacy in front of goal in the opening matches of the season before answering his critics by breaking his duck in last week's 7-2 win over Falkirk.

And any lingering doubts about a crisis of confidence were banished tonight when he came off the bench to grab the winner in Aberdeen after just three minutes on the pitch.

McLeish - who brought Boyd to Rangers in January 2006 - is well aware the striker has suffered his fair share of criticism but insisted: "We have seen similar strikers throughout history, players like Coisty and Tony Cottee.

"People were always looking for something more, something extra. But these guys will put the ball in the back of the net and players like that are few and far between.

"I had hoped the substitutes would make an impact and Boyd more than did that. It was a great goal."

Boyd's goal tally for Scotland has been impressive and McLeish added: "Six goals in 10 games is a great record and the competition is intensifying for front places.

"We said last year that we didn't have an out-and-out goalscorer but Kenny Miller has scored a few, Craig Beattie looked bright and Boyd came up trumps again."

Derby's Jay McEveley and Dundee United skipper Barry Robson both made their international debuts, while Alan Hutton of Rangers earned his first start for Scotland.

McLeish said: "Jay McEveley didn't do himself any harm and Barry Robson never looked fazed. I also thought Alan Hutton was excellent. I think we can take a lot from tonight's game."

The one sour point of the evening was the sight of South Africa striker Sibusiso Zuma leaving the pitch on a stretcher following a crunching tackle from behind from Russell Anderson.

South Africa coach Carlos Alberto Parreira was unhappy with the challenge but McLeish defended the Sunderland defender.

He said: "I asked Mr Parreira how Zuma was and he said he was okay. He didn't say anything to me about the tackle. It was a strong tackle but it happens in the game.

"I don't think Russell Anderson is a malicious player. He has been hard but fair throughout his career."

But Parreira insisted: "The game was mostly played in a very fair manner but a foul like that shouldn't happen in the game.

"We lost our best striker after 10 minutes and we missed him a lot. He has scored five goals in our last three or four games and we lost that power.

"We had many chances but could not finish them."

However, Parreira - who led Brazil to World Cup glory as a coach in 1994 - backed the Scots to qualify for next summer's European Championships.

He said: "They are doing well in a very tough group, which also includes France, Italy, Georgia and Ukraine.

"Scotland still have a possibility of qualifying but they have to go with their own style, which is a very direct game."