Celtic turned in a stubborn defensive display to earn a wonderful Champions League draw at the Nou Camp.
Barcelona dominated the first period and Samuel Eto'o put them in front, but Magnus Hedman made two good saves.
Then, in a rare attack, John Hartson prodded in a Stilian Petrov free kick on the stroke of half time to level.
Failure to win means Celtic cannot reach the knockout stages but they are one point ahead of Shakhtar Donetsk in the race for a Uefa Cup place.
The home side started the game in confident style, zipping the ball around and pinning Celtic back in their own half.
But, for all their possession, Barca were slow to threaten Hedman.
In the first 20 minutes, it was Celtic players who were causing problems for their keeper, with Jackie McNamara and Neil Lennon playing uncomfortable balls back to Hedman.
Alan Thompson tried his luck from all of 30 yards but Barca keeper Victor Valdes held the shot with ease.
The Spanish league leaders sprang to life in the 25th minute when Eto'o and Deco exchanged passes and the Cameroon striker burst through the middle of the Celtic defence to slam the ball home.
Eto'o should have grabbed another goal a minute later when he steered a cross from Silvinho wide from six yards.
Ronaldinho then superbly picked out Ludovic Giuly in behind the Celtic defence but Hedman raced off his line to block the Frenchman's shot.
Ronaldinho was again the provider when Eto'o was found in a central position 10 yards from goal but Hedman stopped the striker's shot with his legs.
Celtic had barely ventured into the Barca half but found themselves level a minute before the interval.
Petrov swung in a free kick from the left flank, Varga got the slightest touch with his head and Hartson was free at the back post to tap in from close range.
Barca saw the lion's share of the ball after the break but Hedman was not troubled until a tame Ronaldinho free kick sneaked round the defensive wall in the 63rd minute.
The Catalans had lost some of their sparkle and Celtic were winning more tackles in the midfield area to interrupt their flow.
A 76th minute shot from Xavi took a deflection which wrong-footed Hedman but the ball flew two yards wide.
Barcelona substitute Iniesta broke purposefully towards Hedman's goal but Bobo Balde managed to crowd the youngster out.
Another vicious deflected effort from Xavi then looped up onto the roof of Hedman's net as Celtic were camped around their own penalty box for the final few minutes.
And Celtic held on for a valuable first away point in nine attempts in the Champions League.
Barcelona: Valdes, Belletti, Puyol, Oleguer,
Sylvinho (Van Bronckhorst 45), Xavi, Marquez, Deco,
Giuly (Iniesta 60), Eto'o, Ronaldinho.
Subs Not Used: Ruben Martinez, Gerard, Fernando, Messi, Rodri.
Goals: Eto'o 25.
Celtic: Hedman, Agathe, Balde, Valgaeren, Varga (Camara 65),
McNamara, Petrov, Lennon, Thompson (Wallace 86), Sutton,
Subs Not Used: Marshall, Juninho Paulista, Pearson, Laursen,
Goals: Hartson 45.
Ref: Lubos Michel (Slovakia).