Another Patrick Dangerfield masterclass has put a triumphant Geelong into a preliminary final, and ended Sydney's season in emphatic fashion after a big semi-final upset at the MCG on Friday night.

The 2016 Brownlow Medal winner kicked four first-half majors as the Cats raced out to a six-goal lead at half time and never looked back, romping home by 59-points, 15.8 (98) to 5.9 (39).

Stung by criticism of their capitulation to Richmond last week, Geelong came ready to play in this cut-throat final, and Chris Scott's men put in a complete performance to leave the Swans looking like the team who couldn't win a game in the first six rounds of the year.

Harry Taylor kept Lance Franklin competely blanketed, and ultimately goalless, after getting the key defensive job when Tom Lonergan was a late out due to food poisoning.

But it was Dangerfield who stood up first on the big stage when the game was in the balance early.

The champion started in the forward 50 at the opening bounce, and gave Dane Rampe a torrid time throughout the first half, taking contested marks, winning a number of free kicks and kicking a swag of goals.

Steve Motlop was also brilliant for Geelong, kicking an inspirational third-quarter goal and setting up numerous forward-50 entries with some magical footwork and kicking.

The Cats next head to Adelaide for a rare finals appearance outside of Victoria, and must now be considered a serious chance of pinching a Grand Final spot from the Crows.

The Swans picked a terrible time to have a shocker after looking one the League's most elite teams over the last three months, and head into the off-season with a number of questions hanging over their list.

More to come.

GEELONG      3.0   9.4    13.4   15.8 (98)
SYDNEY        2.2   3.4     4.9    5.9 (39) 

GOALS
Geelong: Dangerfield 4, Menzel 2, Menegola 2, Duncan 2, Stanley, Smith, Motlop, Hawkins, Blicavs
Sydney: Jack, McVeigh, Mills, Papley, Reid 

BEST 
Geelong: Dangerfield, Henderson, Menegola, Duncan, Motlop, Blicavs, Taylor
Sydney: Hannebery, Lloyd, Jack, Kennedy 

INJURIES 
Geelong: Lonergan (food poisoning) replaced in selected side by Rhys Stanley, Tom Stewart (hamstring)
Sydney: Nil

Reports: Nil 

Umpires: Rosebury, Nicholls, Meredith

Official crowd: 55,529 at the MCG