West Coast coach Adam Simpson concedes his team took a step backwards after conceding 17 consecutive goals during their 101-point western derby loss to Fremantle at Optus Stadium.
The Eagles kicked the first two goals of Saturday night's match, but it was one-way traffic from that point on as the Dockers soared to the 20.14 (134) to 4.9 (33) victory in front of 51,172 fans.
It marked West Coast's biggest ever derby loss, eclipsing the 75-point defeat to the Dockers in round 18, 2010.
The derby ledger now stands at 32-25 in West Coast's favour, but Fremantle can continue to close that gap over the coming years given the long rebuild that faces the Eagles.
"It fell apart," Simpson said of the goal avalanche.
"We couldn't handle their pressure, the contest. The danger sign after the 15-minute mark was probably the ease of which they scored.
"It was too easy and then the floodgates opened for the next two-and-a-half quarters, and you get what you deserve.
"It was not a great day. We took a step backwards today."
Dockers forward Lachie Schultz won the Glendinning-Allan medal as best afield after tallying five goals, 24 disposals, three clearances and seven inside 50s.
"It's good to see him get that reward for effort, because he's a heart and soul player," Dockers coach Justin Longmuir said.
"He commits and values the right things in the game. He's leading the comp in forward 50m tackles, and I know he's leading it in desperate acts."
Fremantle ruckman Luke Jackson, who tied with Schultz in the vote but lost on a countback, was also influential with 19 possessions, 26 hit-outs, six clearances and a goal.
Jye Amiss and Sam Sturt booted four goals apiece, with Fremantle winning the inside 50m count 64-35.
Eagles midfielder Tim Kelly booted his team's second goal at the 14-minute mark of the opening quarter.
West Coast's next goal didn't come until the four-minute mark of the final term when Andrew Gaff dribbled one through from close range.
The listless performance marked yet another low point in West Coast's doomed season, with the Eagles (2-19) to receive the wooden spoon unless they can upset the Western Bulldogs (away) or Adelaide (home) in the final two rounds.
West Coast defender Tom Cole could be suspended for his first-quarter dump tackle on Jye Amiss, while Fremantle veteran Michael Walters could be in trouble for his sling tackle on Alex Witherden.
In a bizarre lead-up to the game, West Coast withdrew Jack Petruccelle due to tonsillitis, and then lost defender Brady Hough just seconds before the opening bounce due to illness.
Hough's withdrawal was so late that it created confusion on the sidelines, forcing the start of the game to be delayed by two minutes.
When the derby action finally got underway, West Coast dominated the early stages, with Fremantle's first inside 50m not coming until the 13th minute.
The scoreboard read 14-0 in favour of West Coast at that point, but it was a purple avalanche from then on as Fremantle went on a goal frenzy.
Eagles forward Oscar Allen came off late in the match after appearing to injure his right elbow.
