Fielding first, Brisbane Heat restricted Stars to 141 for seven with the spin-duo of Yasir Shah and Mitchell Swepson returning with the figures combined figures of 4-0-30-4.
Kevin Pietersen added 30 on his return to the side after being dropped from the last game, while Glenn Maxwell smashed 50 off 39 balls.
In reply, Lynn and McCullum smashed 101 runs for the first-wicket partnership before McCullum fell for 61 off just 30 balls. Lynn combined with Joe Burns to steer Gabba based side home inside 15 overs to seal third victory of the season.
Meanwhile, Stars remain winless after three games.
Mitchell Swepson was adjudged man of the match for his stunning spell of three for 14.