Having lost 15 of their last 16 encounters against the Giants, the Suns snapped a 12-year losing run in the 'Expansion Cup' at People First Stadium.
Gold Coast briefly conceded the lead late in the second quarter, but were otherwise untroubled in securing the 11.17 (83) to 8.15 (63) win on Sunday night.
Melbourne premiership hero Petracca continued his outstanding start to his Gold Coast career, racking up 29 disposals and slotting two crucial goals.
But former Western Bulldogs forward Ugle-Hagan played an equally important cameo, kicking two goals in a third-quarter blitz and adding the matchwinner late on for his third of the night.
It was only the second match for the Suns for the once-troubled Ugle-Hagan, after he debuted for the club in a heavy loss against Hawthorn last week.
"To get another opportunity, second chance," Ugle-Hagan told Fox Footy.
"Been looked after, 'Dimma (coach Damien Hardwick) has looked after me and welcomed here with open arms.
"This club's amazing."
Dashing defender John Noble should find himself in the votes come Brownlow Medal night, after racking up 35 disposals and bombing a long-range goal.
The injury-hit Giants were made to pay for inaccurate early kicking. They dominated from midway through the first quarter until halftime but had only 3.10 to show for their efforts.
Giants star Clayton Oliver, coming up against his former Demons teammate Petracca, battled hard for 32 possessions and nine clearances.
Oliver was involved in a bizarre scrap with Ben Long in the final quarter, when the Suns forward ended up slapping the GWS midfielder in the face and indicating he did it by accident.
Suns utility Sam Clohesy faces a nervous wait after laying a huge tackle that ended up concussing Giants winger Ryan Angwin.
Dazed following the incident, Angwin was placed in concussion protocols soon after leaving the field in the third quarter.
Gold Coast, early premiership favourites after winning their first three matches, had lost three of their previous four games.
But the victory surges them to fifth on the ladder ahead of a clash with St Kilda in Darwin next Saturday night.
The Giants, missing a stack of talent, slumped to 3-5 and sit 14th as they prepare to host struggling Essendon next Saturday.
"The reality is, it's been an incredibly tough start to the season for us," Giants coach Adam Kingsley said.
"We've had some players out, and we haven't had players play together for very many games.Â
"When we start to get a bit more synergy, we'll be fine."
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