Aussie Rules: Geelong have reached their first AFL Grand Final in 12 years, but they had to survive an almighty scare from a Collingwood side which featured former Down minor Martin Clarke.

Paul Medhurst kicked a goal with 70 seconds remaining to close the gap to just five points - with Geelong in front 13-14 (92) to 13-9 (87) - and the siren arrived with Collingwood in search of a winner to end a classic preliminary final in front of 98,000 supporters at the MCG.

The Cats will face Port Adelaide Power in the final next Saturday at the MCG.

Port Adelaide smashed the Kangaroos in the second preliminary final at AAMI Stadium on Saturday, running out winners by 87 points - 20-13 (133) to 5-16 (46).

The Power outscored the Roos eight goals to one in the third term.