The Eagles struggled for accuracy early in the game, kicking four straight behinds before Riccardi added Geelong's third at the 13-minute mark with an impressive left-foot snap from a tight angle.
Matera, who was being manned by Bairstow, finally scored West Coast's first goal at the 20-minute mark when he ran onto a hit-out from Barnes at the edge of the centre square, steadied and kicked truly from 55 metres.
Geelong were first on the scoreboard two minutes into the second quarter when Ablett finished off a fine sequence of midfield play by slotting a wonderful set shot from outside the 50-metre arc on the right half-forward flank.
However, their persistence finally paid off when Matera gathered the ball from a ground level contest on the half-forward flank, used his explosive acceleration to escape from Bairstow, and snapped his second goal on the run from outside 50.
Matera marked and played on immediately, his glorious kick on the run from outside the 50-metre arc curling back between the big sticks for his third goal to give West Coast a lead they would never again relinquish.
Geelong fans were hoping for a repeat of their team's last quarter heroics from 1989, but it was West Coast who got the important first goal within the opening minute when Mainwaring and Lewis combined superbly to find Sumich on a lead.
Brownless, who had been relatively quiet since the second quarter, finally broke the Eagles' run of goals with a superb set shot from the forward pocket after Kemp had been penalized for deliberate out of bounds.