The Scotland international’s goal in the final minutes of the encounter proved to be the difference between the two sides at Celtic Park.
The 25-year-old striker did not start the Scottish Premiership game and came on as a half-time substitute, as the Bhoys ended the match with 10 men.
Griffiths was delighted to have made a scoring comeback from injury and has revelled in his success against Thistle on Twitter, with Celtic fans responding to his message.
Back with a bang. Delighted to start off 2016 with a goal. 20th of the season so far, let's get more #9— leigh griffiths (@Leighgriff09) January 2, 2016
@Leighgriff09 100% could see the difference in the 2nd half! Welcome back griff!— Siobhan Minney (@SiobhanMinney) January 2, 2016
@Leighgriff09 20th goal and it's my 20th birthday on Monday I'm just going to take that as a birthday goal— soph (@sophtrainer) January 2, 2016
Over the course of the 90 minutes at Celtic Park, hosts Celtic had 57% of the possession, took 12 shots of which six were on target, and earned four corners.
Ronny Deila’s side are at the top of the Scottish Premiership table at the moment with 46 points from 20 matches.
The Glasgow giants are three points clear of second-placed Aberdeen and also have a game in hand.