The Saints 8.13 (61) went down to the Cats 17.17 (119).
It was the third time the two sides had met in a VFL/AFL final – on all three occasions the Cats have won. Geelong also defeated St Kilda by 44 points in the 1968 first semi-final and accounted for the Saints in the 1991 second elimination final by seven points.
Although the match loomed as a beauty, considering Geelong and St Kilda were the two most in-form teams entering the finals, the Cats showed they remain the team to beat in 2008 with a stunning display.
After a three-goal lead at quarter-time, Geelong took its game to another level, booting 13 goals to four in the second and third terms, ending any hope of a St Kilda victory.
The only positive for the Saints is the fact they are still in the finals hunt, although they are now into the do-or-die phase.
Capping off a disappointing day for the Saints, defender Jason Blake suffered what appeared to be a wrist injury mid-way through the final term. He was forced to the sidelines, ending his day and potentially his finals series.
And despite Geelong's comprehensive victory, it too finished the match with some serious injury concerns.
The biggest set-back was to emerging midfielder Brent Prismall, who suffered what appears to be a year-ending knee injury. Prismall suffered the injury during the first quarter, in an innocuous incident, where he pivoted and attempted to baulk St Kilda superstar Robert Harvey.
Defender Darren Milburn also had his own concerns, playing out the match with an injured thumb, while Paul Chapman had Steve Johnson, both had hamstring concerns. Chapman appeared to have tightness in the leg, with Johnson suffering a cork.
But it was Geelong's brilliant on-ball brigade that shone on the day, with Jimmy Bartel (34 disposals and two goals), Gary Ablett (35 touches), Joel Corey (32) and Cameron Ling (24), all on song.
Big men Brad Ottens (three goals), either up forward or in the ruck, and Cam Mooney (three majors) were excellent. First-year Geelong defender Harry Taylor also did a fine job on St Kilda captain Nick Riewoldt. Milburn was also among Geelong's best.
For the Saints, Sam Fisher (31 disposals) and Brendon Goddard (23 touches), two of their standouts this season, battled hard throughout the match. Lenny Hayes and Clinton Jones were also solid contributors.
The Saints scored the first goal of the match via Adam Schneider, but it was their only major during this period, in a high-pressure opening.
St Kilda's defence was continually under the pump, as Geelong had 10 scoring shots to two. Still, the Saints remained in the contest, considering the Cats were unable to fully capitalise on the scoreboard, converting just three goals.
As a result, Geelong led by just 18 points at the first change.
Ottens extended Geelong's lead early in second term, although when Stephen Milne snapped St Kilda's second for the day; the margin was cut back to 17 points, lifting the hopes of the Saints.
But when Mooney and Ottens became multiple goalkickers, the Cats jumped out to a 38-point lead.
Xavier Clarke may have reduced the deficit back to 32 points, having kicked truly in time-on, but the Saints needed to lift considerably, if they were to get back into the hunt after the long break.
Unfortunately for the Saints, this didn't occur.
Although Goddard offered a glimmer of hope with the first goal of the second half, when Geelong piled on nine of the remaining 10 goals before three quarter-time, the match was done and dusted.
Geelong led by a whopping 76 points entering the final term and a record losing margin in a final loomed for St Kilda – its worst loss was 80 points against the Brisbane Lions in the 2004 second qualifying final.
But the Saints showed some character in the last term, booting three goals to one, although it mattered little in the finish.
Geelong 3.7 7.10 16.15 17.17 (119)
St Kilda 1.1 3.2 5.5 8.13 (61)
GOALS
Geelong: Mooney 3, Ottens 3, Bartel 2, Lonergan 2, G.Ablett, Chapman, S.Johnson, Ling, Rooke, Stokes, Varcoe
St Kilda: Milne 2, X.Clarke, R.Clarke, Goddard, Montagna, Riewoldt, Schneider
BEST
Geelong: Bartel, Ottens, G.Ablett, Mooney, Corey, Milburn, Taylor, Ling
St Kilda: Goddard, S.Fisher, Jones, Hayes
INJURIES
Geelong: Prismall (knee), Chapman (hamstring), S.Johnson (corked hamstring), Milburn (thumb)
St Kilda: Blake (wrist)
Reports: Hayes (StK) for striking Selwood (Geel) in the third quarter
Umpires: Kennedy, Meredith, McInerney
Official crowd: 71,653 at MCG
The views in this article are those of the author and not necessarily those of the club.
