Swan Districts leapfrogged East Fremantle into second spot on the ladder after crushing Peel by 99 points on Saturday.
Swans established an early ascendancy and finished all over the Thunder to win 22.14 (146) to 7.5 (47) at Steel Blue Oval.
A top-two finish is a priority for the black and whites, who have a bye in the next round and could slip to third if the Sharks beat South Fremantle at East Fremantle Oval on Saturday.
"That top-two spot is crucial to any season," coach Greg Harding said. "It's a long way off. I think we only clawed back five or six per cent on East Fremantle and Claremont are going to be pretty hard to catch in their current form.
"At the moment, all we can do is try to keep winning and let results take care of themselves."
A dominant midfield of Shaun Hildebrandt, Marlon Motlop, Tom Roach and co-captain Josh Roberts was the driving force behind Swans' 12th win.
Hard-running wingman Hildebrand led the possessions with 38. He also had 13 marks and delivered the ball inside 50m four times in an impressive all-round display.
Roach, 37 possessions and 12 marks, Motlop, 32 touches and seven inside 50s, and Roberts, 27 possessions, 10 tackles and six inside 50s, were all busy as ruckman Wes Lammie created plenty of opportunities with 38 hit-outs.
Full-forward Ashley Hansen kicked six goals before being rested in the final quarter. The 29-year-old spearhead remains a key to the premiership with 57 goals in 10 games, including 11 in round 13 against Peel and hauls of seven against Perth in round 11 and Subiaco in round 19.
Defenders Justin Simpson, Tallan Ames, Kyle Hams and Jarrad Blight were in miserly form for Swans. Hams also kicked two goals.
Simpson shut down State forward Brad Holmes, while Ames bounced back to form against West Coast's Scott Lycett after lowering his colours to Subiaco's Jack Anthony in the previous round.
West Coast veteran Andrew Embley was steady in his second game back from injury, looking ready for an AFL recall after 20 possessions and six marks.
Peel were outclassed in just about every position, caretaker coach Mark Moody powerless to stem the tide of goals.
The Thunder didn't kick their first goal until 28 minutes into the second quarter.
Exciting teenager Dayle Garlett, expected to be drafted in the top 10 at this year's AFL national draft, was lively in the reserves for Swans with 16 possessions, four marks and five inside 50s. He kicked 4.3.