Geelong have underlined their AFL premiership credentials with a high-octane 27-point win over fellow fancies Sydney.

Nine days after a scintillating thumping of reigning premiers Brisbane, the Cats backed that victory up in style.

Geelong were ominous at times in claiming a 15.17 (107) to 12.8 (80) victory, their fourth win on the spin, in front of 35,869 fans at GMHBA Stadium.

Chris Scott's Cats (32 points) move to third behind second-placed Sydney (36) and leaders Fremantle (40) ahead of facing Carlton at the MCG next Friday.

Sydney's Malcolm Rosas limped off in the second quarter with a left foot/ankle concern, Tom Papley (calf tightness) sat out the final term, and Angus Sheldrick came off late.

Cats defender Lawson Humphries was sensational, collecting 33 disposals and 818 metres gained.

Midfielder Max Holmes (35 disposals, eight clearances, 712 metres gained) was exceptional, while Jeremy Cameron (three goals, 21 disposals) and Gryan Miers (11 marks, 24 disposals) were influential.

Geelong blanketed Swans spearhead Charlie Curnow (two goals), thanks to Connor O'Sullivan and Jake Kolodjashnij - a late call-up for Tanner Bruhn (managed).

Tagger Oisin Mullin went to Swans superstar Isaac Heeney (23 disposals, one goal).

Sydney stopper James Jordon kept Bailey Smith to eight disposals for the first half, then the tag was dropped and the Cats star had 18 touches and a goal in the third quarter and finished with 32 possessions.

Half-backs Riley Bice (34 disposals) and Callum Mills (24 disposals) were busy for Sydney, and Joel Amartey kicked four goals.

Dean Cox's Swans led by four points at quarter-time and Amartey gave Sydney a 10-point lead at the start of the second term.

Then the Cats seized control, nailing five unanswered goals as Sydney struggled to go with their frenetic speed and pressure.

Humphries levelled the scores with a superb long bomb, before Cameron put Geelong in front and the Cats surged.

Heeney goaled after the siren to stop the rot and reduce the deficit to 20 points.

O'Sullivan brought the crowd to their feet when he snapped his maiden AFL goal and wheeled away in childlike delight.

The Cats led by 38 points midway through the third quarter, but Sydney kicked five of the final six goals and Logan McDonald jagged the final two majors of the term, including one after the siren, to cut the deficit to 14 at the final break.

But Cameron sunk a wonderful long bomb, before skipper Patrick Dangerfield buried a superb strike from the boundary to restore a 25-point lead.

The Swans couldn't reel in the Cats and will lick their wounds before hosting Richmond on Saturday.