The Scottish club have pulled a few shock results out of the bag
Celtic welcome Barcelona to Glasgow on Wednesday night knowing only a win will leave them in with a chance of playing European football after Christmas.
We look at the history of European games between the teams:
In March 2004, the sides met in the fourth round of the UEFA Cup. The Catalans travelled to Scotland and in an emotional affair - with the game being played a day after the Madrid bombings - Celtic went on to win 1-0. The home side finished the game with just ten men and the visitors with nine after Rab Douglas, Thiago Motta and Javier Saviola were all sent for early showers. Alan Thompson scored the only goal of the match.
Rookie goalkeeper David Marshall manned the posts for the return match and kept a clean sheet to send the Scottish club through on aggregate.
The two sides met again in 2004 as part of the new Champions League season with Barcelona running out 3-1 winners in Glasgow. Celtic battled to a 1-1 draw in the return leg, John Hartson levelling after Samuel Eto'o had given Barcelona the lead.
The teams didn't meet again until the round of 16 in the 2007/08 season when Barcelona progressed 4-2 on aggregate having won both matches: 3-2 in Glasgow and 1-0 at in the Nou Camp.
A four-year gap eventually saw the sides meet in the group stages of the 2012/13 season. Both matches finished 2-1 in favour of the home teams although Barca did need a last minute Jordi Alba goal to secure victory at the Nou Camp.
In 2013, Cesc Fabregas scored the only goal of the game as the visitors triumphed 1-0 at Celtic Park, before Barcelona hammered their rivals at home 6-1 in the return leg of the group stage. The game featured an in-form Neymar who went on to score a 15-minute hat-trick.
Celtic welcome their illustrious rivals tonight needing a win to have a realistic chance of playing European football in the New Year. They shipped seven goals when the teams met in September and failed to deal with the threat of chief tormentor, Lionel Messi.