McGregor has been in a ton of battles throughout his UFC career. Some of the biggest fights in the promotion have happened with him on one side, and he was asked who his toughest opponent was.
McGregor named Nate Diaz as the toughest star he had faced to date.
McGregor and Diaz have met twice in the UFC and both matches have been incredible. However, McGregor was keen on fighting Diaz for a third time, and had glowing praise for the American.