As the Hoops full-back jogged for a throw-in, the Jambos supporter runs down the Tynecastle steps to hurl some insults before falling over the stadium railing to make a complete fool of himself.
Not that Izaguirre or Celtic cared, they went on to win 4-0 and book their place in the last 16 of the competition.
Fancy Winning a Copy of Football Manager 2015? Enter Our Simple Twitter Competition:
— talkingbaws (@talkingbaws) December 1, 2014