Fanning came top of the heat with a 14.50 total and went on to win the final against John John Florence, Julian Wilson and Matt Wilkinson.
Christie’s 13th-place result backed up a ninth and a third in the previous two QS events and pushed him up to 25th on the QS rankings ladder.
This was not enough to secure a top-10 finish and automatic requalification, but Christie has one more opportunity to move into the CT top 22 from 30th.
He has to win the last event of the 2015 CT — the Pipeline Masters in Oahu — and other surfers ranked higher than him will have to bow out early in the competition.
The Pipeline Masters is scheduled to start on Tuesday and finish by December 20.