Norton, Massachusetts - A contrite Luke Donald apologised on Sunday for slamming golf course architect Gil Hanse in a Twitter posting that he thought was private.

England's Donald had bogeyed the par-five 18th hole at the TPC Boston on Saturday, a hole that Hanse had reconfigured with a smaller green featuring steep slopes away from the playing surface.

Donald said he thought he was sending a direct message on Saturday night to Hanse via the social networking site, but instead the public tweet started with Donald's cellphone number and then said: “Gil Hanse is a (expletive). Haha.”

Donald quickly deleted both tweets and on Sunday apologised to Hanse and anyone else who might have been offended.

“I didn't mean to put it out there, and I apologise to anyone I offended, especially Gil Hanse,” he said.

Donald said he received numerous phone calls soon after posting his own number, but he wasn't complaining.

“That's what I deserve,” he said. - Sapa-AFP