West Belconnen's win shut the door on the Yass Magpies' hopes of sneaking into the top four, with the Magpies edging the Goulburn Bulldogs 28-22 at Goulburn.
They needed a massive win and hope the Kangaroos did the same to the Warriors to have any chance of playing finals.
Kangaroos coach Aaron Gorrell was confident they could turn the result around, but not if they brought a similar attitude.
"We were just dumb, mentally weak, stupid, all of the above. We've just got a couple of people who are all about themselves and need to put the team first or we'll go straight out the backdoor next week," Gorrell said.
"We got everything we deserved today so back to the drawing board and hopefully we get a change of attitude.
"We just expected to win and took them too lightly, and didn't want to do the hard work to earn the right to play footy.
"As bad as we played, we had many chances in the last 10 minutes to go ahead, but we were just too stupid.
"You go from a chance at minor premiers to third because you have an easy day."
News of the result filtered through to Phillip, giving the Rams a second chance.
It's the first time they've made the semis since 2009 and the first time all three grades made the finals since 1993.
Rams coach Ash Barnes rested veteran halfback Lincoln Withers, which meant Jackson McDonald - son of former Canberra Raider Darrell McDonald - made his debut.