Darren Clarke has fired caddie John Mulrooney, the man with whom he won the Open Championship six months ago.

Since that historic victory, it's been a struggle for the Ulsterman, who has seen his form take a serious dive.

Friday's 81 at the Abu Dhabi HSBC Championship, his worst round in five years, appears to have been the last straw.

Mulrooney, a fellow Irishman, linked up with Clarke by chance at last May's Mallorca Open when Mulrooney suddenly found himself available after David Howell withdrew. Clarke needed a bagman as his then caddie, Ricci Roberts, went to Orlando for the investiture of Ernie Els into the World Golf Hall of Fame.

Clarke won that tournament and Mulrooney suddenly found himself with a new full-time employer.

Despite Clarke's historic Open success a few months later, the duo have not been a match made in heaven.

Mulrooney nearly got fired the week before the Open after the two got into a serious disagreement on the final day of the Scottish Open. They also fought at October's Grand Slam Championship in Bermuda.