Celtic bounced back from their 3-1 Europa League defeat by Molde to thrash Dundee Utd 5-0 in the Premiership at Parkhead.
The Hoops are now four points clear of Aberdeen at the top of the Premiership while United remain rooted to the foot of the table – five points adrift of Partick Thistle – after a ninth defeat in 12 matches.
Celtic swept into a 2-0 lead with goals from striker Leigh Griffiths and defender Dedryck Boyata.
Kris Commons, who issued a public apology for his reaction to being substituted against Molde, scored a penalty just before the interval and then grabbed a second in the 53rd minute before skipper Scott Brown netted with a deflected shot a minute from time.
Championship result
St Mirren vs Rangers - 0-1