Celtic score four to reach 10 wins in a row
Ryan Christie was on target as Neil Lennon's men secured top spot in their Europa League group against Rennes on Thursday and the Scottish international midfielder took his tally for the season to 15 with a first half brace.
Christie was fortunate to smash home the rebound after Nathan Baxter had initially saved his penalty to open the scoring on 11 minutes.
However, the Staggies quickly hit back as Celtic conceded in the league for the first time in six games when Ross Stewart headed home a free-kick.
Christie put the visitors back in front before the break when he latched onto Kristoffer Ajer's defence-splitting pass.
Tom Rogic then made the game safe as his deflected effort found the bottom corner 23 minutes from time.
And Mikey Johnston rounded off the scoring just seconds after coming off the bench with a brilliant individual run and finish.
Victory sees the Hoops open up a three-point lead over second-placed Rangers, but the Glasgow giants could be tied at the top again come the end of the day as Steven Gerrard's men host Hearts at Ibrox later on Sunday.