The Lions scored the first 45 points in a ruthless first quarter before the Eagles stemmed the flow in a 16.20 (116) 5.5 (35) win at the Gabba on Saturday.
Hawthorn recruit Gunston was dropped a month ago after a quiet start as a Lion, restricted purely to training in an effort to freshen the 31-year-old, three-time premiership player.
It seemed to work, Gunston (20 disposals) snapping two first-quarter goals before finding more ball at halfback and squeezing two more through in the second half.
He iced his comeback with a further two majors in the final minutes to complete his bag.
It was only the fourth six-goal haul for Gunston in his 14 seasons, a career-best seven evading him when a long set shot sailed wide with 20 seconds to play.
Gunston got his chance with Lincoln McCarthy suspended and Callum Ah Chee (concussion) injured and Melbourne at the MCG will be a more formidable foe should coach Chris Fagan retain him next week.
The Lions kicked seven goals in the first 20 minutes but, against a side that's already been on the end of four 100-plus point losses this season, missed a chance to truly boost their percentage.
Brisbane enjoyed an embarrassment of possession but relied on the Eagles' unforced errors for many of their later goals.
Harris Andrews (19 disposals) again flirted with the AFL record of 10 intercept marks in a commanding defensive performance, while Cam Rayner (one goal, seven inside 50s, four score assists) was bullish but lacked polish in front of goal.
Jeremy McGovern (20 disposals) was an uninjured substitute after playing three quarters in his first game since a round-three hamstring injury, while fellow returnee Tim Kelly (26 touches, 12 contested, one goal) clashed heads with Gunston in the first term but recovered to be one of his side's best.
Eagle Oscar Allen kicked a goal to keep his season streak alive while Brisbane defender Brandon Starcevich booted one too, only his sixth in 87th AFL appearances.
Hugh McCluggage was heavily involved early and rewarded with two first-quarter goals to continue his mid-season resurgence, but both Charlie Cameron and Joe Daniher were kept goalless in front of 24,843 fans.
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