Gibson produced his worst round of the week by seven shots Sunday to go from 19-under and sharing top spot to 16-under and T26.
American Anders Albertson fired a final round 8-under 63 to grab the victory by two shots from Adam Long and overnight co-leader Kramer Hickok.
The poor play will be more costly for Gibson than just this week’s cheque, however, the 32-year-old also falling out of the top 25 money leaders who will be promoted to the PGA Tour at the end of the season.
With low scoring once again the order of the day Gibson was in early trouble with a bogey at the third and compounded that error with three more against a lone birdie.
Two high finishes to start the season had Gibson in good position to earn promotion to the main Tour but a run of middling results had seen him slip to 25thon the money list to start the week.
Through three rounds it looked like Gibson would be assured of moving up the standings even if he didn’t hang on for the win but with only one player posting a worse score Sunday it was a damaging collapse.
Gibson is now 28thon the money list and while there are seven events left on the schedule to play his way back in he will need to recover quickly.
Sydney’s Jamie Arnold overtook Gibson to claim Australian bragging rights for the tournament with a T11 finish.
Arnold posted a final round of 3-under 68 but slipped four places down the leaderboard.
Curtis Luck was the last of the Australians to make the cut and finished T53 after a final round 66.
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