The negative reception to the president came in spite of Trump's early support for the sport who hosted its events when other venues and legislators shunned the UFC.
Numerous videos posted on social media showed the crowd booing when President Donald Trump arrived for the UFC fight at Madison Square Garden in New York City.
Newsweek spoke to Chatri Sityodtong, founder and chairman of ONE Championship.
McGregor made history in New York on Sunday morning.
McGregor clashed with Diaz at the press conference for UFC 202.
The Irishman announced his retirement on Tuesday.
Dana White, UFC president, confirmed McGregor's withdrawal on Tuesday.
This is what happens when two unpredictable talkers come together.
Like McGregor, the Californian has a penchant for trash talk.