Celtic survived the controversial dismissal of Daniel Majstorovic to restore their four-point lead at the top of the table by beating Inverness.
Joe Ledley's 16th-minute tap-in after a James Forrest cross proved crucial.
Charlie Mulgrew went close to extending the lead with a couple of long-range efforts with Celtic in control.
Majstorovic was shown a red card for a disputed 60th-minute challenge on Jonny Hayes, but Caley Thistle's Steve Williams was sent off 17 minutes later.
And with that went their chance of causing an upset, or at least preventing Celtic extending a run of consecutive league and cup victories to 17 and restoring their advantage over reigning champions Rangers, who had beaten Dunfermline Athletic 4-1 earlier in the day.
Majstorovic had replaced the injured Thomas Rogne, but Celtic were otherwise unchanged following their midweek dismantling of Hearts.
Caley Thistle manager Terry Butcher rang the changes after last week's Scottish Cup capitulation by the Scottish Premier League leaders.
Ryan Esson returned to goal at the expense of Jonathan Tuffey, while recent signing Claude Gnakpa was given a start along with Williams and Shane Sutherland as Gregory Tade, Ross Tokely and David Proctor dropped out.
Esson was immediately under pressure and a Victor Wanyama header flew just over the crossbar from a corner.
Gnakpa found Nick Ross in acres of space just outside the Celtic box, but the midfielder failed to control the ball instantly and the chance was gone.
Inverness were threatening to put up stiffer resistence than they did a week earlier until Scott Brown's pass put Forrest behind the Caley Thistle defence and the winger's ball across the face of goal was guided into the net by Ledley.
Mulgrew forced Esson into a fine save just under the bar from a whipped-in free-kick and the defender came close again when he drilled a 25-yard shot low past the far post.
Majstorovic was sent off in controversial circumstances shortly after the break when he clashed with Hayes as the winger nipped in behind the Sweden defender.
Inverness almost immediately wasted a chance to level when Gnakpa fired into the side-netting after being found by Williams but with a couple of team-mates waiting for a pass in front of goal.
Caley Thistle only kept their man advantage until the 77th minute, when Williams was shown his second yellow card of the game after barging into Geogios Samaras.
Ross sliced wildly wide and then was expertly ushered off the ball inside the box by Mulgrew just as the midfielder fancied his chances of an equaliser that never came for the visitors from Inverness.