Hardwick had a horror 1-9-1 record as coach at the AFL-owned venue since his infamous declaration - when in charge of Richmond four years ago - that he hated playing there.
But Suns captain Noah Anderson and former skipper Touk Miller helped ensure Hardwick's fortunes were reversed in an important 12.8 (80) to 8.13 (61) victory on Sunday.
In doing so, Gold Coast moved to 8-2 for the first time in the club's 15-year history and maintained third spot on the ladder in pursuit of a maiden finals berth.
Hardwick's men have two further games at Marvel this season - against Essendon in round 17 and Carlton in round 22 - which could have a huge bearing on their top-four aspirations.
Fans gave the Sunday evening timeslot the thumbs-down, with only 13,486 turning out.
It was St Kilda's lowest home crowd in Melbourne since 2002, outside the pandemic-impacted 2020-21 seasons.
Suns guns Anderson (36 disposals, 11 clearances) and Miller (30 touches, one goal) starred in the midfield and Ben Long kicked three majors against his former team, while Sam Collins marshalled the defence.
The only sour note for the Suns was a suspected right ankle injury to key defender Mac Andrew, who limped off with five minutes left in his 50th game.
Gold Coast had two goals on the board in the opening 90 seconds and never trailed, leading by 18 points at the first break and 29 at half-time.
Their connection and conversion were features as they posted 7.2 to 0.2 from set shots in the first half, albeit with a couple more attempts that failed to score.
St Kilda fought back into the contest in the third quarter and dominated possession for a period, but often let themselves down with poor execution in the front half.
They posted a wasteful 1.6 to 0.2 for the term, trimming the margin to 19 points at the final change, and drew within 13 when Cooper Sharman opened the scoring in the last quarter.
But Suns spearhead Ben King, who was otherwise blanketed by Callum Wilkie, replied with a steadying goal and the visitors hung on.
King finished with two majors, giving him 31 for the season to keep pace with Geelong's Coleman Medal leader Jeremy Cameron, who has 33.
Sharman was the Saints' most dangerous forward but hit the post twice in kicking 3.3 from 13 possessions.
Nasaiah Wanganeen-Milera had a career-high 35 disposals and one goal, with Jack Steele (33 touches, one goal) and Jack Sinclair (29, one) also busy for St Kilda.
