The much-hyped 19-year-old gathered 20 possessions, most of them in the midfield, earning 66 Fantasy points, a spot among his team's best players and praise from his boss.
"He doesn't lack any confidence ... but that's good," Roos coach Brad Scott said after the game at Eureka Stadium in Ballarat.
"I'd much rather players that have self-belief, and Luke's got that.
"But he's got that for a reason. He's a good player already, and we're just going to have to keep working with him.
"He knows the step up, even from our match-simulation stuff to today, was pretty significant, and it goes up another few notches from here.
"But he's ticking every box that we put in front of him at the moment, so as long as he keep doing that, then the future's bright for him."
Asked if round one was a realistic goal for McDonald, Scott said: "I think it's a realistic goal, because his performances at training and again today were pretty good.
"But he's going to have some pretty stiff opposition, I'd suspect.
"I think we'll have a number of players come into the side next week, and we're already squeezing that into 26.
"We've got squeeze that into 22 (for the premiership season), so that'll be a good challenge for him, but he tends to rise to challenges."
Scott was also delighted with rookie-listed backman Joel Tippett's first game for the Kangaroos.
Tippett, the 25-year-old brother of Sydney Swans forward Kurt Tippett, held Carlton's Jarrad Waite to just two kicks, two marks and no goals.
"We thought he was the best key defender outside the AFL last year," Scott said.
"He's done it the hard way. He's been rookie-listed twice, he's moved away from his home state to go and play in South Australia to further his cause, and he's determined that he's going to take this opportunity.
"So he slotted in and played on a really good player today and showed good athleticism and good ability in the contest.
"But, really, he just replicated today his training form over the pre-season, so that's why we were keen to get him in the 26 today."
Nick Dal Santo was North Melbourne's other eye-catching recruit. He finished with 27 possessions and 89 Fantasy points.
"Dal did a bit of everything," Scott said. "That's one of the things that we really like about Nick – that he can play in multiple positions.
"He can play where we need him to play."
Nick Dal Santo shone in his first outing for North Melbourne in the NAB Challenge. Picture: AFL Media
Carlton coach Mick Malthouse was similarly delighted with the efforts of his club's mature-age recruits.
Former Western Bulldog and Sydney Swan Andrejs Everitt earned high praise after kicking three first-half goals.
Rookie-listed ruckman Cameron Wood, who played under Malthouse at the Magpies before being delisted after Nathan Buckley took over as coach, also did what was asked of him.
Having spent last year playing for Williamstown in the VFL, Wood celebrated his return to the highest level by winning 19 hit-outs and booting the last goal of the game, which enabled the Blues to hold off the fast-finishing Kangas.
"He's a maturing ruckman," Malthouse said. "He's slotting in beautifully.
"He's a young man who's now gone on and felt what it's like to not be part of an AFL football club.
"His contesting today was very good."
Tom Bell and Dylan Buckley were other players to earn a positive appraisal from Malthouse.