In 2010 in Vancouver, he let the emotion of the crowd and fighting in his home province get to him in his second UFC outing. Veteran Carlos (The Natural Born Killer) Condit rallied to put MacDonald away with just seven seconds remaining at UFC 115.
Against (Ruthless) Robbie Lawler at UFC 167 in Las Vegas in 2013, a lacklustre training camp was followed by an uneven performance that was not helped by a third-round poke in the eye. MacDonald had his moments but not enough of them and lost a split decision.
Now MacDonald (18-2) is getting a second crack at Lawler, this time for the welterweight championship. The 25-year-old Montreal-based fighter has been matched against Lawler (25-10 with one no contest) in the co-main event of UFC 189 on July 11 in Las Vegas.
"I'm going to be a much better fighter for this one," MacDonald said in an interview Thursday, one day after the fight announcement.
His first meeting with Lawler, however painful, proved to be worthwhile.
"I'm grateful (for) the experience I had that night with Robbie," MacDonald said.
"It really was a kick in the ass and a blessing in disguise. I was upset about it but I can't explain how much that motivated me to get myself back into where I need to be. I wasn't at my best for that fight and it was my fault."
After the Condit loss, MacDonald learned not to bring emotion into the cage with him. His normal pre-fight demeanour is so cool that the ringside doctor might be tempted to feel for a pulse.
But against Lawler, he could not wait for training camp and fight night to be over "so I could go relax and just get away from martial arts for a bit."
In the wake of the loss, he adopted a new attitude.
"Just having fun with martial arts and getting back to that passion and enjoying my life in martial arts," he said. "That's all."
So far so good.
MacDonald has posted impressive wins over Demian Maia, Tyron Woodley and Tarec Saffiedine since losing to Lawler.
He has also managed to keep his enthusiasm despite the UFC changing its mind twice on his title shot. An interim fight with Hector Lombard slated for UFC 186 in April in Montreal was pulled when Lombard tested positive for steroids.
There was a silver lining, however, as MacDonald learned of his title opportunity at the same time as hearing Lombard had failed his drug test.
Still he acknowledges the uncertainty over his schedule tested his focus. He decided just to concentrate on the fight in front of him, whatever it was, "and do my thing like always."
Featherweight champion Jose Aldo will face rising Irish star (The Notorious One) Conor McGregor in the UFC 189 main event.
MacDonald's hope is the UFC's planned enhanced drug testing will be in place for the MGM Grand Garden Arena card.
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