Ipswich will meet Gaters for a place in the Brisbane Rugby League grand final after accounting for Wynnum Manly Redland City 32-24 at BMD Kougari Oval on Sunday.
The Jets held off a fast-finishing Seagulls side to earn the right to choose their week two opponents.
They chose to face elimination final winners Gaters, meaning Wynnum Manly will play local rivals Easts Tigers - the second elimination final winner - for the other grand final spot.
Gaters ended Redcliffe's season with a nail-biting 26-20 upset at Langlands Park on Saturday, with an attacking master class from fullback Marlon Doak the difference between the two sides.
Doak, who returned from Intrust Super Cup duties with the Dolphins, picked up from where he left off earlier in the season.
With Gaters ahead 12-10 at the break, he chipped and regathered to score before setting up winger Adam Wickens minutes later.
When nuggetty winger Shaun Rees crossed in other corner, they held a 26-10 lead.
However, the Dolphins mounted a surge and almost pulled off a remarkable comeback.
Two quick tries saw them reduce the margin to just six, with Gaters drawing on gallant goal-line defence in the final minute to hold on for the win.
In the second elimination final, Easts progressed with a 28-18 victory over West Brisbane Panthers, setting up a clash with Wynnum Manly.
The return of speedsters Maeli Seve and Brandon Downey gave the Tigers too much finishing ability out wide.
Easts coach Jason Di Lizio said he was quietly confident despite a less-than-ideal preparation.
“We had a bit of a disrupted preparation during the week with a couple of the guys having the flu and missing training,” he said.
“But we got through and now it’s another opportunity for us at this time of the year and another challenge. We’ve been getting better and better each week and we’ll need to lift against next week.”
In the qualifying final, Ipswich centre Pat McCallum nabbed a first half hat-trick for a 20-6 halftime lead over Wynnum Manly.
The score was locked at 24-all with twenty to play before a determined run from David Tahavalu and Haydan Lipp penalty goal got the Jets home.
FINALS WEEK ONE RESULTS
Saturday, September 5
GATERS 26 (Marlon Doak, Adam Wickins, Kieran English, Shaun Rees, Stephen Tunnicliffe tries; Joshua Cattell 3 goals) def REDCLIFFE DOLPHINS 20 (Marty Hatfield, Kyle van Klaveren, Hayden Hansen, Ashley Harawira tries; Jordan Mitchell 2 goals) at Tapout Energy Stadium, Langlands Park, Stones Corner.
EASTS TIGERS 28 (Maeli Seve 2, Brandon Downey, Whetu Austin, Leon Ellia- Niukore tries; Brandon Downey 2, Jayden Carroll 2 goals) def WEST BRISBANE PANTHERS 18 (Luke Pollock 2, Luke Brookes, Robbie Lane tries; Jake Dornan goal) at Tapout Energy Stadium, Langlands Park, Stones Corner.
Sunday, September 6
IPSWICH JETS 32 (Pat McCallum 3, David Tahavalu, Fine Faingaa, Sean Hams tries; Haydon Lipp 4 goals) def WYNNUM MANLY REDLAND CITY SEAGULLS 24 (Jeriah Goodrich, Chris Green, Braydon Greenhalgh, Patrick Matulino tries; Chris Green 4 goals) at BMD Kougari Oval.
FINALS WEEK TWO
Friday, September 11
Preliminary Final: Wynnum Manly Redland City v Easts Tigers at BMD Kougari Oval, 7.30pm
Sunday, September 13
Preliminary Final: Ipswich Jets v Gaters at North Ipswich Reserve, 11.30am