Coming off three matches where they had performed poorly in the first half, the Falcons turned that form around to lead the Sharks at every change in a 16.9 (105) to 10.13 (73) victory in difficult conditions at Arena Joondalup.
The triumph moved the side to second place after round nine, which, interestingly, was the position they held after nine rounds in 2013 when they won the premiership.
But that parallel means nothing in the context of a particularly challenging 2015 race, with only two wins currently separating West Perth from as far down as eighth spot.
Only in their win against easy-beats Perth had the Falcons led at the end of every quarter prior to their success against East Freo on Saturday.
The Sharks had not lost at Arena Joondalup since 2009.
West Perth forward Matt Fowler kicked three goals, equal with Aidan Lynch who has settled comfortably into the league ranks this year after being named the best player of the 2014 reserves competition.
Aaron Black led the Falcons� midfield with 26 disposals and two goals, while Chris Keunen emerged from a tight battle against Sharks ruckman Robert Young with 43 hitouts to Young�s 42.
WAFL action gives way to national football this weekend when WA faces South Australia at Lathlain Park on Saturday.
Falcons players Black, Keunen, Laine Rasmussen, Jay van Berlo, Shane Nelson and Andrew Strijk were named in the preliminary 36-man squad, which is mentored by West Perth premiership player and coach Darren Harris.
West Perth face East Perth when WAFL resumes for round 10.