Kotoni Staggs starred in Australia's 44-12 semi-final win over Samoa, his best World Cup display.
The 28-year-old had missed six weeks before the tournament and needed time to find his feet.
Staggs said: "I think the Samoa game was just about being more relaxed and calm."
He added: "I just worried about my job and what I can do for the team, not anything else."
Brisbane finished 14th, and Staggs had represented NSW twice before being dropped for the State of Origin decider.
Kevin Walters coached him at Brisbane for three seasons and selected him for the World Cup on his form in Australia's 3-0 Ashes win last year.
Staggs said: "I didn't know what was going to happen, but obviously Kev stuck with me from the Ashes series."
He said he had played some of his best football under Walters, who trusted that history.
Australia's right edge struggled in its first two pool matches, but Staggs, Tom Trbojevic, Liam Martin and Tom Dearden improved their defensive combination.
Staggs said the players came from different systems but built greater trust and communication during the tournament.
At Suncorp Stadium, his home ground, Staggs is confident ahead of Sunday's final against New Zealand centre Casey McLean and ready to repay Walters' faith.