South Augusta's bid for a sixth consecutive SGL A Grade premiership came to an end at the hands of a hungry Proprietary/Risdon team, who booked their spot in the Grand Final with a 50-point win.
The Bulldogs won the first quarter and were still in the game at halftime, but were put to the sword in the third, and the Lions then romped to a famous 14.19 (103) to 8.5 (53) victory.
It was a cathartic win for Props, who were beaten in last year's decider by South, and now go on to face Solomontown in an all-Port Pirie Grand Final.
Luke Edwards stood tall for Lions with three goals, while Anthony Oliphant, Hugo Wallace, Ryan Finn and Jordan Fuller had two each. Oliphant had a cracking game for Props and was deservedly named the Best On Ground.
Ethan Reid had two goals for the Bulldogs, while Caleb Ritter, Jaylon Wingfield and James Weir battled hard all day but couldn't help South recover from Lions' third quarter blitz.
South were also without key player Kirston Thompson, who was reported in their Qualifying Final loss to Solomontown, which made their task even harder.
The game was umpired by representatives from Adelaide, and the umpires will also be officating the Grand Final bewteen Lions and Sollies in Port Augusta this weekend.
After five premierships in five years South overcame some early seasons struggles this year to finish second, but will be bitterly disappointed with a straight sets finals exit.
Nonetheless the Bulldogs had to recover from the loss of key players Matt Downey and Clayton Milera to West Augusta, along with Jarryd Warren, Craig Miller and Will Bolitho.
With new recruits needing time to settle in, South had a wonky start to the year, but soon things gelled and the unit were competing with the best in the league.
While a second three-peat is no longer on the cards South will look back on their achievemens over the last five years with pride, and look forward to a new beginning next season.
Meanwhile Lions will try to best Minor Premiers Solomontown for the first time this season when they collide in the Grand Final on Saturday.