A starring display by Tim Kelly has made light of West Coast's injury woes as they secured a 15-point AFL win over St Kilda.
The undermanned Eagles, having lost key defender Jeremy McGovern to a hamstring injury, looked gone as the Saints stormed into a fourth-quarter lead but finished stronger to claim a 9.11 (65) to 6.14 (50) win at the Gabba.
The victory on Thursday night secures West Coast's finals berth for 2020 and they remain firmly in the top-four hunt heading into their last home-and-away fixture against North Melbourne on Thursday.
They'll have to take on the Kangaroos without McGovern however after the 28-year-old limped out of the game late in the second quarter with a right hamstring injury.
McGovern's absence adds to an injury list including Dom Sheed, Luke Shuey and Elliot Yeo as well as Lewis Jetta and Brandon Ah Chee.
"One of our best wins for the club in my time," 2018 premiership-winning coach Adam Simpson said.
"Really brave effort ... I think it was our youngest side for I don't know how many years, missing some players and the Saints threw everything at us as well.
"Lost Gov early. The guys just played their roles, played with real spirit."
Without so many of their top-level midfielders, it was big-money recruit Kelly who stood up for the Eagles in a best-on-ground display.
Kelly had 29 disposals, six marks and nine clearances as well as kicking a vital fourth-quarter goal for the Eagles.
Andrew Gaff (33 disposals, one goal) and ruckman Nic Naitanui (33 hitouts, nine clearances) were also influential for the Eagles.
West Coast pair Oscar Allen and Jack Darling were the game's only multiple goalkickers, booting two goals each.
Defeat leaves St Kilda's top-eight hopes on a knife edge heading into their last home-and-away match against GWS.
After sitting inside the eight since round four, the Saints are now just four points clear of the eighth-placed Giants having played one game more as they try to end a finals drought stretching to 2011.
Saints coach Brett Ratten said a goalless second-term, where the Eagles dominated contested footy, had given West Coast the confidence they needed.
"The mood of the rooms was sombre, as it should be," Ratten said.
"That second quarter where we just got beaten around the ball, whether it was in the air or on the ground, they flipped probably the first quarter into the second quarter their way and that really changed the momentum of the game and gave him a huge advantage."
Despite going goalless again in the third term, the Saints looked the likely winner as they kicked themselves ahead with a flurry of three goals in the opening seven minutes of the final term.
Playing their fifth game in 19 days, the Eagles looked shot but key forward Josh Kennedy and Kelly got their team back in front as they closed out a gutsy win.