The remarkable 9.18 (72) to 10.9 (69) win was led by a stunning final quarter comeback to overrun the Mandurah Mustangs to win the premiership.
Victory was clinched when Baldivis dominated the final term with 12 shots on goal to two.
A strong third term by the Mustangs appeared to propel them to the flag, but Baldivis lifted when it mattered most.
Baldivis dominated the final quarterto win the gruelling contest by just three points.
The Mustangs initially qualified for the grand final with a thumping 53-point win over Rockingham in the preliminary final.
In the league grand final, Pinjarra defeated Waroona 15.14 (104) to 12.7 (79).