Celtic survive late scare to battle back against St Johnstone
Second-placed Rangers were hosting St Mirren in a later kick-off, with a chance to reduce the deficit.
Brendan Rodgers' men trailed to Diallang Jaiyesimi's first goal for St Johnstone at half-time after failing to deal with an in swinging corner.
But Callum McGregor netted with a powerful strike in the 67th minute and Matt O'Riley hit his seventh Premiership goal of the season 12 minutes later when he finished brilliantly from 22 yards.
The final outcome hinged on two incidents in time added on.
Saints substitute Jay Turner-Cooke headed off the post from close range before Celtic broke seconds later and Tomoki Iwata squared for fellow sub James Forrest to guide the ball home.
Rodgers said he was furious with his team after a sub-par performance in the first half.
"I think that's the angriest I've ever been as a manager at half-time," he told Sky Sports. "At this club the standards are very high. Our levels need to be much better.
"It's a reminder that teams in this league can hurt you when you drop off.
"You must have that intensity from the first whistle, but the reaction in the second half was really good."
