The win was set up by a four-goal first term to Brendon Goddard and the Saints' best-ever quarter against the Eagles in the second, when they booted 10 goals straight to the visitors' two.
So dominant was the Saints' display, they nailed 13 consecutive goals through the second and third terms, and overall they registered 68 tackles to 44 as well as recording 107 more possessions.
The 25.11 (161) to 9.10 (64) win saw the Saints shelve a hoodoo of sorts which had seen them lose five of their past six clashes with West Coast.
The victory also saw them build on an impressive record at their home ground, where they've now won 11 of their past 15 matches.
They also recorded their biggest score since round 17, 2006, and their second biggest win over the Eagles in their history.
Goddard was outstanding in the first quarter after starting in attack. He attracted a range of opponents and relished his new role up forward to register a personal best tally in front of goal.
He ended the game with four majors and 28 touches.
Clinton Jones was outstanding on the dangerous Daniel Kerr, racking up an incredible 14 tackles, and becoming one of the Saints' 15 individual goalkickers.
Former Eagle Michael Gardiner kicked two goals, while Nick Riewoldt had 11 contested possessions.
It wasn't the way Eagles midfielder Tyson Stenglein (15 touches) wanted to spend his 200th AFL match, although teammates Matt Priddis (30 disposals) and Mark LeCras (three goals) tried valiantly to lift the side in the second half.
Adam Selwood spent time on both Nick Dal Santo and Leigh Montagna, but each was able to shake his presence and end with 31 touches.
The Saints got the early jump through Goddard, who had two goals on the board within three minutes, but the Eagles soon responded with majors to Adam Hunter and Mark LeCras.
By quarter time, the Saints led by 16 points and from there, it was party time for the home side.
The Saints kicked an incredible 10 goals in the second term with Koschitzke going to half time with three, Stephen Milne with two and Steven King, Jarryn Geary, Adam Schneider, Riewoldt, Gardiner and Montagna one apiece.
After kicking the first goal of the second term in the opening minute through LeCras, the Eagles did not score another six-pointer until the 11-minute mark of the third when Quinten Lynch marked and kicked truly.
The Eagles rallied after that and equalled the Saints' third-term return of five goals, which saw them trail by 66 points at the final change.
The Saints ended the game in style with a five-goal final stanza – with Zac Dawson kicking his first goal in AFL football – and the Eagles managing just three behinds.
St Kilda will now host Fremantle at Docklands next Saturday night while West Coast will play the Western Bulldogs at Subiaco on Sunday.
ST KILDA 5.2 15.2 20.7 25.11 (161)
WEST COAST 2.4 4.5 9.7 9.10 (64)
GOALS
St Kilda: Goddard 4, Koschitzke 4, Milne 4, Gardiner 2, Riewoldt 2, Schneider 2, King, Montagna, Geary, Gram, Jones, Hayes, Dawson
West Coast: LeCras 3, Hunter 2, McKinley 2, Lynch 2
BEST
St Kilda: Montagna, Jones, Goddard, Dal Santo, Blake, Gram, Gwilt
West Coast: Priddis, LeCras, Cox, Lynch
INJURIES
St Kilda: Nil
West Coast: Nil
Reports: Dal Santo (St Kilda) for striking Stenglein (West Coast) in the third quarter, Dal Santo (St Kilda) for wrestling Stenglein (West Coast) in the third quarter, Stenglein (West Coast) for wrestling Dal Santo (St Kilda) in the third quarter, King (St Kilda) for striking Hansen (West Coast) in the fourth quarter
Umpires: James, Sully, Grun
Official crowd: 29,006 at Docklands
