Kelechi Iheanacho came off the bench to score the winner against Hibs
As Martin O'Neill stressed again, there is "little margin for error" in this unprecedented three-team race for the Scottish Premiership title - and his Celtic side continue to make fewer of them than their rivals in recent weeks.
The reigning champions made heavy weather of overcoming a Hibernian side who suffered a fourth red card in three games after only 21 minutes at Easter Road on Sunday.
But, having gradually eaten into Hearts' title lead, Celtic's 2-1 win means the long-time pacesetters are only now ahead on goal difference.
With Rangers four points adrift of them both, the pressure is on Celtic's city rivals - as well as their hosts - at Tynecastle on Monday.
