In his first game since being shifted from fullback, Trbojevic came alive either side of halftime and had a hand in two tries at Brookvale Oval.
Manly were far from their best, but after a fortnight of spotlight on coach Anthony Seibold they are back in the top eight following a win the hosts desperately needed.
The result also consigned the Tigers to their sixth straight loss, who desperately missed Jarome Luai in attack after he was ruled out on gameday.
Adding to the Tigers' concerns was a concussion for Api Koroisau, which has the potential to stifle any chance of fellow hooker Tallyn Da Silva leaving before the June 30 deadline.
But all eyes were always going to be on Trbojevic and the Manly coach's box on Friday night.
'Turbo' got the ball in good shape just once in a scoreless 39 minutes, when he was whacked by Jeral Skelton and coughed up possession.
But when the Sea Eagles finally utilised the fullback-turned-centre again, the game started to turn.
The only first-half try came through 28-year-old Trbojevic, who got the ball 10 metres out and put Jason Saab over to score.
Trbojevic then began to roam in the second half, combining with new No.1 Lehi Hopoate for a Reuben Garrick try when he roamed from right centre to the left.
Another Manly try came down the left after Trbojevic had again created numbers early in the set, before Luke Brooks and Daly Cherry-Evans helped Tolu Koula score.
Manly have been adamant all week Trbojevic's move was a short-term one, designed to put confidence back in the 2021 Dally M Medallist's game.
The Sea Eagles have South Sydney next Sunday, before another bye.
"We'll do it again next week and then we'll have a rethink after the bye," Seibold said after the win.
"Everyone has been telling me for the past 18 months you need to move Turbo to centre, and then I do it I get criticised.
"I just want him to enjoy his footy.
"It was great to see him get across and have a bit of freedom, he didn't have to worry about organising our defence."
There were still some questions over Trbojevic's defence, with the visitors' first try coming when Adam Douiehi put Alex Seyfarth past him and into a gaping hole.
Hopoate had his toughest half of the season wearing No.1, dropping two kicks after being virtually unblemished while playing their previously, while Manly also fear prop Nathan Brown suffered a possible season-ending biceps rupture.
While the Tigers are clearly an improved outfit, they have now lost six in a row and will likely face the Sydney Roosters next week without Koroisau and Luai.
Da Silva scored late out of dummy-half but looks likely to leave the club by year's end, while Latu Fainu lacked spark without Luai next to him.
Luai was hospitalised with a boil infection, but the Tigers expect him to be fit for State of Origin III on July 9.
"We were left in a bit of a scramble with Jarome pulling out this morning," coach Benji Marshall said.
"We didn't have enough experience in those positions today to get it done. We got dominated in field position.
"The last few weeks have been really good, today was a step backwards."
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