David Turnbull scored his first Celtic goal as the Hoops overcame Lille 3-2 to end their Europa League campaign on a high note and ease some of the pressure on Neil Lennon.
A dismal run of form has piled the pressure on Celtic boss Lennon and, despite a spirited display from his youthful side, it looked as though they would be extending their winless run to six matches.
Timothy Weah's maiden Lille goal – a fantastic volley from just inside the area – had made it 2-2, cancelling out Callum McGregor's first-half penalty, which came at the end of a frenetic seven-minute flurry in which Christopher Jullien and Jonathan Ikone also netted.
Lille looked well placed to push on and seal a win which would have seen them top Group H when Weah, son of Liberia legend George, struck against his former club, yet Turnbull's neat finish in his first European appearance secured a hard-fought Celtic triumph.
Celtic had the lead after 21 minutes – Julien heading in from Turnbull's fantastic left-wing corner.
Yet their advantage lasted under three minutes, with Yusuf Yazici taking advantage of McGregor's mistake by squaring for Ikone to tuck in.
Domagoj Bradaric's clumsy tackle on birthday boy Jeremie Frimpong gifted Celtic the opportunity to restore their lead, though, as McGregor atoned for his error with a composed finish.
McGregor got lucky when he diverted Cheikh Niasse's cross off Conor Hazard's left-hand post, before Turnbull saw a close-range shot deflected wide at the other end.
But Lille had a second equaliser when Celtic failed to clear a free-kick and Weah lashed in on the volley.
Celtic did not let their heads drop, though, and Turnbull was on hand to sweep home from Kristoffer Ajer's cross with 15 minutes remaining – Isaac Lihadji subsequently squandering a golden chance to snatch a point for Lille.
What does it mean? Lille miss out on top spot, Hoops avoid club-low
Celtic, who avoided losing a fourth straight home match in continental competition for the first time, finish bottom of Group H, but with four points – one more than their lowest tally in a European group.
Lille, meanwhile, have to settle for second place, with Milan having overcome Sparta Prague 1-0 to clinch top spot, and potentially an easier draw in the knockout stage.
Turnbull turns on the style
Former Motherwell midfielder Turnbull had stayed on the bench for all five of Celtic’s Europa League matches before Thursday’s clash, but he gave Lennon plenty of food for thought with a superb performance.
Playing in a free role off the striker, Turnbull had four attempts in total and created a joint team-high three chances.
Birthday blues for injured Frimpong
It was a 20th birthday spent in the wars for the versatile Frimpong. After clattering into the hoardings early on and taking a nasty blow to the head, he had to be withdrawn after sustaining an injury while drawing the foul which led to Celtic's penalty.
In his 30 minutes on the pitch, Frimpong had 12 touches, attempted five passes and lost possession six times.
Celtic take on Kilmarnock as they aim to get their domestic form back on track, while Lille host Bordeaux in Ligue 1.