Josh Treacy has broken through the Western Bulldogs’ flood in his 100-game milestone as Fremantle all but sealed the minor premiership with a 37-point win at Optus Stadium.

Fremantle’s perfect record in Perth this season was under threat in Friday night’s blockbuster after the Bulldogs’ flooding tactics ensured scores were level at half-time.

But spurred on by 53,524 fans, Fremantle kicked seven goals to one in the second half to secure the 11.12 (78) to 5.11 (41) win.

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While key forwards Jye Amiss (0.1 from six disposals) and Pat Voss (1.0 from eight disposals) struggled in the flooded forward line, Treacy used his big frame to take some important contested grabs on the way to 3.2 and eight marks to go with 13 disposals.

Treacy’s contested mark above three opponents and subsequent goal early in the final quarter gave Fremantle a 19-point buffer, and more importantly finally broke the spirit of the flood.

It sparked a four-goal burst from the Dockers as they extended their record at Optus Stadium to 11-0 this season.

The win guaranteed a top-two berth and two home finals for Fremantle (18-2).

And if Sydney (14-5) lose to St Kilda on Saturday, the Dockers will be crowned minor premiers with three rounds still remaining.

The Bulldogs (12-8) face North Melbourne, Carlton and Melbourne in their final three rounds, and they may need to win all three in order to snare a top-six berth and avoid the wildcard round.

Ed Richards (26 disposals, nine clearances, 752m gained) and Tom Liberatore (28 disposals, six clearances) racked up big numbers for the Bulldogs, while Cooper Hynes kicked two goals from 22 disposals in the absence of Aaron Naughton and Cody Weightman.

Fremantle star Luke Jackson (26 hitouts, five clearances, 16 disposals, two goals) edged Bulldogs big man Tim English (27 hitouts, one clearance, 15 disposals) in an intriguing ruck battle.

Fremantle won the inside 50m count 15-6 in the opening quarter, but their only reward for effort was a late Jackson goal as the Dockers went into the first break with a one-point lead.

There was plenty of push and shove late in the second quarter when Voss gave Richards a bit of extra treatment after the Bulldogs star had been caught holding the ball by Caleb Serong.

Serong kicked the goal while Voss was in the thick of a mini melee, but Fremantle’s 12-point lead vanished in an instant as Rhylee West and Rory Lobb kicked late goals to level things up by half-time.

Fremantle skipper Alex Pearce needed running repairs in the second quarter after dislocating a finger on his left hand while bravely flying into a pack for a mark.

Only two goals were scored in the third quarter - both to Fremantle - and Bulldogs coach Luke Beveridge cut a frustrated figure due to his team’s costly mistakes.

First, Rory Lobb’s attempt to square the ball to a teammate in attack went horribly wrong, with the ball flying over Richards’ head before Laitham Vandermeer fumbled the bouncing ball.

It allowed Fremantle to swing it all the way into attack for Treacy to take a strong mark and kick a goal.

Then late in the third quarter, Sam Davidson’s attempted square kick across the Bulldogs’ defence instead landed in the lap of Serong for another easy goal.

It meant Fremantle’s lead was 14 points at the final change, and a powerful mark in attack to Treacy early in the last quarter proved to be the moment that broke the Bulldogs’ spirits.