Celtic overcome Partick challenge
There were a couple of efforts early on as Teemu Pukki tested Scott Fox and Thistle striker Lyle Taylor - who has joined on loan from Sheffield United - fired over at the other end.
Stuart Bannigan and Lyle Taylor both threatened for Thistle as they looked to get on the front foot, before Christie Elliott's header forced Fraser Forster into action.
Celtic's Kris Commons was offering an attacking threat but it was to be fellow midfielder Ledley (39) who was to open the scoring, the Welshman drilling home from the edge of the box.
Charlie Mulgrew almost marked his return to the home side's starting line-up with a goal, first from a curling free-kick and then from a marginally offside position.
Pukki tried his luck from 18 yards, forcing Fox to punch clear but Commons was just unable to latch onto the rebound.
Elliott fired an effort over the bar as the clock ran down but one goal was to prove to be enough for Celtic to maintain their 11-point advantage at the summit.