MacDonald had no problems with British striking specialist Che Mills, pounding him out on the mat en route to a second-round TKO victory.
Ref Mario Yamasaki stopped the bout at 2:20 of the round after Mills took a barrage of unanswered strikes.
"I could tell I was landing big shots, and I when I land shots on the ground and they're clean, I know they're going to be hurt," MacDonald said.
The first was all MacDonald. The Canadian welterweight showed great ground and pound from the top, at one point pushing aside Mills' attempted triangle and diving into a hard right. Mills then moved into side control and got the crucifix position briefly. Mills regained his left hand but MacDonald stayed in side control. With about 30 seconds left he got full mount and Mills gave up his back, but MacDonald couldn't finish.
By the time the round was over, Mills had a cut on his forehead and hemotoma on his right cheek.
The second was more of the same. MacDonald got an easy takedown and this time overwhelmed him until the finish.
"Che was a great opponent. He didn't get much respect in the media because of his lack of fights in the UFC," he said. "But I took this fight very seriously."
MacDonald is now 13-1 overall with his third straight win. Mills fell to 14-5 with one no contest.