Fulham vice chairman Tony Khan replied to criticism after his side's latest Premier League defeat by telling a fan to 'go to hell' on social media.
Khan told a fan to "go to hell" in a tweet after the 2-1 loss to Burnley left the London club with only one win in nine English Premier League games on Saturday.
Burnley profited from two own-goals in quick succession to come from behind and leave Fulham five points from safety.
Khan tried to ease concerns of fans by promising "multiple signings to improve the squad" in the January transfer window while stressing on Twitter: "It's on our players now to fight, finish & win."
But the son of American owner Shad Khan reacted angrily to one supporter responding: "Leave my club please."
Tony Khan, who is director of football operations at Fulham, replied : "Never. I'll die at this club. Go to hell."
Responding to criticism over the tone of his tweet, Khan complained the fan was among those who "give no credit when things go well, including giving me stick immediately after promotion."
Fulham could be making an instant return to the second tier after their latest setback.
Andre Schurrle's early opener for Fulham was cancelled out in the 20th minute when Jeff Hendrick's effort went in off Joe Bryan.
Three minutes later, Denis Odoi inadvertently beat Sergio Rico, heading in after Hendrick crossed.
Burnley held on to record a third consecutive league victory, further easing their own relegation fears.