The Dolphins leapfrogged the Roosters into fourth position and confirmed their credentials as premiership contenders in front of 20,687 fans at Suncorp Stadium on Friday night.
The Roosters lost debutant centre Reece Foley and five-eighth Hugo Savala to head knocks in the first half. The visitors trailed 12-0 at halftime before the Dolphins put their foot down with six second-half tries.
Both sides were heavily impacted by State of Origin commitments with the Roosters losing seven to NSW and Queensland. Five Dolphins are in camp in Melbourne with the Maroons.
Katoa, who had been on standby for Blues playmaker Miitchell Moses during the week, had his fingerprints all over the win.
"He's outstanding," Dolphins coach Kristian Woolf said.
"I said before he went into the Blues camp that I was really proud of the fact he got to do that. He knows he's on the cusp of it and he gets real confidence out of that. He played that way tonight."
"He's got a little medial issue there that he just twinged scoring the try. We took him off a little bit early as a precaution when the game was won. He'll be okay, but he'll be a little bit modified this week."
Katoa's halves partner Kodi Nikorima was also superb, showcasing why he deserves an extension beyond 2026.
"It's something we're trying to work out with him. I love Kodi, love what he brings to the team and I love watching him and Isaiya play together," Woolf said.
Dolphins co-captain Katoa stepped up with a subtle dummy to deceive opposite number Daly Cherry-Evans to open the scoring.
Dolphins points-scoring whiz Jamayne Isaako, who injured a finger in the final play of the game, converted to equal Canterbury legend Steve Gearin's all-time premiership record by scoring in his 94th consecutive match.
"He's got a bit of an issue there that we'll have looked at tomorrow," Woolf said of the Isaako injury.
"The docs are pretty confident with him. I think it dislocated, but it's not a fracture."
The kamikaze running of pocket rocket fullback Trai Fuller got the Dolphins roaring up field to start a set that finished with a try out wide to centre Herbie Farnworth, his sixth of the season.
Roosters debutant winger Rex Bassingthwaighte, just 19, looked every bit the talent he has been touted as with a try, dynamic bursts and all-round nice touches.
"He was involved a lot and is constantly asking questions. What a great start," Roosters coach Trent Robinson said.
The Dolphins started the second half superbly with Katoa and Nikorima combining. Second-rower Oryn Keely split the defence to send Fuller in for his first try of the year.
Katoa's inch-perfect chip for Nikorima to score his 50th NRL try was scintillating. Hooker Jeremy Marshall-King barged over from close range, Farnworth split the defence to send second-rower Connelly Lemuelu over and winger Tevita Naufahu's kick inside for utility Brad Schneider was a pearler.
Naufahu's 100m chase to deny Roosters fullback Cody Ramsey a try revealed the Dolphins' resolve in defence.
The loss of Hugo Savala to a head knock meant the Roosters had a third debutant in the match with playmaker Toby Rodwell, 20, coming on in the second half and scoring a try to showcase his class.
"Toby is such a good young player," Robinson said.
"He has done it in reggies and SG Ball. He is a nice footy player. It was so great to see that."