(REUTERS) - Ireland's Conor McGregor has told Dustin Poirier their third fight scheduled for July 10 is off after the pair quarrelled on Twitter over a US$500,000 (S$671,000) donation to the American's charity.
Former two-weight Ultimate Fighting Championship (UFC) champion McGregor said earlier this month that a third fight was booked with Poirier, who became the first man to knock him out in January.
McGregor knocked Poirier out in a featherweight contest in 2014.
But McGregor was not happy when Poirier said the Irishman had not made good on a promise to donate to his charity.
"A donation, not a debt. We've been awaiting the plans for the money that never came," McGregor said in a reply.
"500k with no plan in place," he added.
"The fight is off... I'm going to fight someone else on the 10th."
Poirier replied by saying McGregor's team "never responded" to e-mails explaining where the funds would go.