Robert Allenby has split with his caddie after an argument midway through his opening round at the Canadian Open.

A dispute about club selection ended with Allenby, who started his round on the back nine, taking Mick Middlemo's advice before finding the water with an 8-iron on the par-five 13th.

"I said to him, 'You know this happens every week. This has happened for like the last three or four or five months. We keep making bad mistakes, and you're not helping me in these circumstances, and he just lost the plot at me. He just told me I could go eff myself," the Australian told ScoreGolf.com.

"And I said, 'Look, you need to slow down. I mean just calm down.' And then he just got right in my face as if he wanted to just beat me up," he said. "I said, 'Stop being a such and such and calm down and get back into the game.' And he just got even closer and closer, and I just said, 'That's it, you're sacked.' I said, 'I will never have you caddie ever again.'

"We never spoke for the rest of the [first nine], and when we got to 18 we walked off, and he said some smartass remark to me, and I said, 'You don't deserve to be caddying out there.' And he just got right in my face and threatened me, so I said, 'Go.' So he left."

A fan served as Allenby's caddie for the remainder of the day as the 44-year-old carded a nine-over 81.