Celtic got back on track after a difficult week as Brendan Rodgers' side clinched a 3-1 win against Partick Thistle in the last 16 of the Scottish League Cup on Saturday.
Rodgers' men lost 1-0 at Hearts in the Scottish Premiership last Sunday before crashing out of the Champions League qualifiers on Tuesday after a 3-2 aggregate defeat against AEK Athens.
It was essential for Celtic to lift the gloom and Leigh Griffiths' goal after 17 minutes gave the Scottish champions the lead on their return to domestic action at Firhill.
Andrea Mbuyi-Mutombo equalised with 18 minuted left, but Moussa Dembele and Tom Rogic netted to get the treble winners back to winning ways.
Celtic will be back in continental action when they take on FK Suduva in the first leg of their Europa League play-off on Thursday.
With one eye on the trip to Lithuania, Rodgers dipped into his squad with Scott Bain, Kristoffer Ajer, Cristian Gamboa, Scott Sinclair, Mikey Johnston and Emilio Izaguirre in the starting line-up.
Celtic took the lead when Scott Sinclair went past Christie Elliott and cut the ball back for Griffiths to fire in from 10 yards for his first of the season and his 99th for Celtic.
Griffiths was replaced by Dembele in the 64th minute and within moments he drew a great save from Cammy Bell with a powerful angled-drive.
Partick hit back when Aidan Fitzpatrick set up Mbuyi-Mutombo and, with the Celtic defence in disarray, fired a low drive in off the far post.
But Dembele eased Celtic's nerves four minutes later when he converted Gamboa's cross from close-range.
Rogic swept the ball past Bell from another Gamboa delivery to make it three and book Celtic's quarter-final place.