The Cats led by 38 points with 18 minutes left on the clock before Carlton came back from the death.
The Blues kicked seven goals on the trot to snatch a two-point lead and what seemed like certain victory in the dying stages of the match.
Matthew Lappin was the hero after he converted from a free kick and dubious 50-metre penalty against Jarad Rooke to give his side the lead for the first time since the nine-minute mark of the first quarter.
But in a match which had more twists than an Agatha Christie novel, the Cats weren't done.
Just 26 seconds remained on the clock when the ball was back in the centre to restart play.
Carlton's Scott Camporeale roved the ruck contest but his kick was smothered by Paul Chapman. Joel Corey gathered the loose ball, handballed to Glenn Kilpatrick, who handballed to David Clarke who kicked to a diving Riccardi on the 50-metre arc.
The lethal left-footer lined up as the siren sounded and floated an ugly punt through to break the hearts of the Carlton army.
Geelong coach Mark Thompson said he wasn't watching when Riccardi kicked.
``I'd got up out of the chair by then and I didn't actually watch it,'' Thompson said.
``I could tell by the emotions of the people around me that it had gone through. It (the feeling) was one of disbelief and excitement.
``I just didn't watch it. Probably didn't want to watch it.''
Thompson said he was pleased it was Riccardi taking the kick.
``It was good it was in his hands, he's a nice kick for goal,'' he said.
Geelong controlled the match for most of the day but lapsed badly in the last quarter when Carlton made its charge.
It led by 15 points at quarter-time and extended that lead to 37 points by three-quarter time.
Captain Ben Graham blanketed Lance Whitnall for three quarters but the Blues' spearhead sparked the fightback with three last-quarter goals.
Leading goalkicker Kent Kingsley was again a focal point up forward with four goals, while Aaron Lord chimed in with three.
Steven King was dominant in the ruck but Geelong didn't always take advantage with Carlton's midfielders picking up plenty of clearances, particularly captain Brett Ratten and veteran Craig Bradley.
Darren Milburn and Brad Sholl held the backline together, while James Kelly did plenty of good things in just his fourth game.