Early goals from Coatbridge bhoys Tony Watt and John Herron secured a 2-1 win for Celtic over St Mirren.
The buddies pulled a goal back just before half time with a shot that deflected past Robbie Thomson but were unable to deny their visitors full points.
The result cuts Hearts lead at the top of the table down to ten points with John Kennedy’s side having three games in hand.
With Marcus Fraser, Dylan McGeough, Paul George and Filip Twardzik with the development squad at Leeds it gave a number of fringe players the opportunity to stake a claim for a more regular place.
Stuart Findlay made a welcome return to the centre of defence alongside Curtis Jones with Bahrudin Atajic partnering Watt in attack as Celtic switched to a 4-4-2 formation.
In the ninth minute Patrik Twardzik opened up the home defence before threading a ball through to Callum McGregor who played the ball across goal for Watt to roll into the net.
Two minutes later Herron took advantage of a slip by the Saints left back to cut into the penalty box, draw the keeper, then slot Celtic two in front.
Celtic were playing their trademark passing game and dominating the match with the midfield setting the pace backed up by full-backs Joe Chalmers and Mikey Miller pushing forward at every opportunity.
Watt, Herron and Jackson Irvine had chances to extend Celtic’s lead before St Mirren tightened things up to restrict the space the visitors were enjoying in midfield.
Without any real warning St Mirren pulled a goal back in the 44th minute when a deflected shot from a corner spun past Robbie Thomson into the net.
Jones almost re-established Celtic’s two goal lead early in the second half but his header brought out a full length save from the home keeper.
Twardzik had two chances to score but saw a 58th minute shot blocked by the keepers legs then shot weakly at goal after the Saints keeper had made a mess of a clearance.
Celtic were pushing hard for the third goal but found their opponents defending strongly without ever posing any real threat of an equaliser.
Substitute Lewis Kidd set up McGregor for a shot at goal in the 82nd minute then saw his own effort scrape the cross bar with five minutes left to play.
CELTIC: Thomson; Miller, Findlay, Jones, Chalmers; Herron, Irvine, McGregor, P Twardzik; Watt (Johnstone 88), Atajic (Kidd 58)
SUBS: Hart, Fisher, Lindsay
CLICK HERE for Crosas introduced at Santos Laguna
CLICK HERE for Alex Salmond tries to sell Hearts to Quatar royal family