McDonald, 19, was one Melbourne's best in their 78-point victory over Greater Western Sydney on Sunday at the MCG.
With regular defenders Jared Rivers and Colin Garland playing up-forward against the Giants, McDonald stepped up, amassing 26 possessions, four marks and three tackles matched up against No.1 draft pick Jonathon Patton.
McDonald has played 13 AFL matches, including 11 this year, after being picked up by the Demons in the 2010 national draft.
Coach Mark Neeld said McDonald had cemented his place in the senior side.
"He is getting the rewards for having an outstanding pre-season," said Neeld.
"We have exposed him to a number of different types of forwards this year and he is improving each week."