East Perth’s finals hopes hinge on a round 21 triumph over Peel after the Royals went down to the Falcons on Saturday.

Luke Webster’s men were in the box seat to lock down a top five spot at Leederville Oval, but a lacklustre third quarter cost East Perth dearly as they slumped to a disappointing 18-point loss to their arch rivals.

The 16.10 (106) to 13.10 (88) defeat essentially makes this weekend’s clash with the Thunder an elimination final – unless Perth musters an unlikely win over the unbeaten Lions.

If that does not eventuate, the winner of Saturday’s encounter at Bendigo Bank Stadium will advance to the finals and the loser will be left to lick their wounds.

East Perth looked like a force to be reckoned with in the opening quarter against West Perth as first-year Eagle Oscar Allen wreaked havoc in the Royals’ attacking arc.

In just his second game starting as a key forward, Allen kicked the game’s opening goal following a strong contested mark and straight set shot from 40 metres.

The 19-year-old continued to cause headaches for his former club as he flew for marks while his black and blue comrades got busy at ground level.

Co-captain Patrick McGinnity, seasoned campaigner Sharrod Wellingham and versatile tall Asher Samelko all hit the scoreboard in the opening term, gifting the home side a 15-point advantage at the main break.

West Perth’s onball brigade found their feet in the second term and started to connect with its forwards, resulting in a four-goals-to-one term and three-point lead to the Falcons at half-time.

They continued their ascendancy in the penultimate stanza, as the likes of Aaron Black and Shane Nelson (37 disposals each) plus Andrew Strijk and Tyler Keitel (three goals each) stamped their authority on the game.

East Perth failed to slow the rampant Falcons, who slotted 10 goals in the second half en route to victory.

Luke Partington (26 disposals), Matt Allen (23) and Brayden Ainsworth (21) toiled manfully the entire day, while Jake Waterman (three goals) and Oscar Allen (two goals) kept the Falcons’ defenders on their toes.

Jarrod Brander clunked eight marks in the defensive half, Josh Rotham effected a team-high six spoils while Jackson Nelson collected 18 disposals and nine half-back rebounds.