With all eyes on Nicho Hynes, it was halves partner Trindall who delivered for the Sharks as they set up a preliminary final against three-time defending-premiers Penrith next Saturday night.
After Cronulla took a 24-0 lead into the break in Friday night's semi-final, North Queensland threatened a second-half comeback when they got it back to 24-12 with 25 minutes left.
But ultimately an uncontestable Scott Drinkwater dropout that went out on the full sealed the Cowboys' fate, allowing to the Sharks to kick 26-12 clear.
North Queensland again hit back to 26-18 with 10 minutes to play but the Sharks were able to hold on and place themselves 80 minutes from a grand final.
Ronaldo Mulitalo got among the scorers as the Sharks built a 24-0 lead by halftime. (Dan Himbrechts/AAP PHOTOS)
The win ended Cronulla's seven-match losing run in finals, and marked their first post-season victory since the semi-finals of 2018.
Friday night had loomed as the Sharks' most important game since the 2016 grand final, given their struggles in finals matches and question marks over Hynes's form.
Hynes was as solid and reliable as Cronulla needed him to be, while Trindall had close to his best game in Sharks colours.
It was after Cronulla's round-seven win over the Cowboys that the 25-year-old was caught driving with drugs and alcohol in his system after celebrating the win.
He spent five weeks out of the NRL, but has begun to fire at the back end of the season.
Braydon Trindall was a star for the Sharks, having come through controversy to the finals. (Mark Evans/AAP PHOTOS)
"It really hurt him for obvious reasons, and so it should have," Sharks coach Craig Fitzgibbon said.
"He took accountability and responsibility for that. And he has done nothing other than try and repay the team."
The five-eighth was superb on Friday night, scoring a double and having a hand in two other tries as he took on more control of Cronulla's attack.
His first of the night came via a penalty try, when he was taken out by Reuben Cotter while chasing through on his own grubber kick.
Another try came when he chased through on his own bomb, stayed alive when Briton Nikora batted it back and Jesse Ramien flicked the ball onto him.
Nicho Hynes responded to criticism with a strong game that included five goals from five attempts. (Dan Himbrechts/AAP PHOTOS)
Hynes' kicking game also came to fore, when Ronaldo Mulitalo out-leapt Kyle Feldt on a bomb midway through the first half.
On that occasion it was Trindall who picked up the loose ball, before flicking it back for Cameron McInnes to reach over the line and score.
And when Trindall helped Kayal Iro send Mulitalo over just before halftime, the Sharks' 24-0 lead appeared unassailable.
While Cronulla were denied twice by the bunker in the second half, Trindall again forced the dropout that allowed the Sharks to take a 26-12 lead.
"To be honest, last week we were disappointed with Tricky's performance. But like Nicho, he owned it," Fitzgibbon said.
"He's a hell of a player. He has been developing along nicely. And tonight his kicking game was strong, his defence was strong.
"The combination with he and Nicho went well, they didn't get in each other's road and used each other really well.
"And when he had a moment, he went for it."
As good as Cronulla were, this was North Queensland's season summed up in a nutshell.
They turned up 40 minutes too late to their most important game of the year, and while a late Reece Robson break gave them hope, it was far too late.
Adding to the pain, departing North Queensland veteran Feldt limped off early with calf damage, while Holmes ended the night on crutches with a lower leg injury.
"The way we started in that first half was too costly," coach Todd Payten said.
"Our good-ball attack put too much pressure on our defence.Â
"Four good sets in that first half came up with errors. We weren't calm enough in those moments."
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