Brendan Rodgers apologised to Celtic supporters after they lost back-to-back league games for the first time in a decade and said his players lacked "desire and passion".
First-half goals from Lawrence Shankland and Stephen Kingsley earned Hearts their first league win at Celtic Park since 2007, opening the door for Celtic's title rivals Rangers, who can go top if they win their two games in hand.
The Celtic supporters turned on the board during the game and booed the players off the pitch after a limp performance that saw the club's 52-game unbeaten league home run come to an end.
"I want to apologise to the support base - I don't think I have ever had to to that with regard to performance but today they deserve it," Rodgers told Sky Sports News after the game.
"It's mid-December and you get, 60,000-odd fans here and the lack of desire and passion was just really really poor. It wasn't the whole team, Callum Mcgregor was brilliant, trying to drive the team on, and one or two others.
