And their isn't time for a restart as the referee blows for full-time!
90' +4
Jordi Alba has scored a goal for Barcelona! Assist by Adriano.
ALBA HAS WON IT! Heartbreak for Celtic and Forster in particular, who has been superb for his side, as Adriano's curling ball from the right-hand side of the area misses everyone but Alba, who manages to guide the ball into the far post via his studs.
90' +3
We are 90 seconds or so away from full-time as Celtic thump the ball clear after another attempted Barcelona attack. Surely they can hold on?
90' +1
J. Forrest gets yellow.
VILLA HITS THE POST! As we enter stoppage time - of which there will be four minutes - another quick passing move from Barcelona finds Villa on the corner of the penalty. The striker drills a low shot across Forster but it hits the far post and spins clear.
90'
Here we go! Hooper breaks and this is his chance! Oh, he tries to trick his way past Mascherano and is halted at the first hurdle. Ah well.
89'
Celtic are just about hanging on here as Alba squeezes past two challenges to get to the byline and test Forster at the near post.
87'
Barcelona are boasting 72 per cent possession tonight, but Celtic's lion-hearted performance continues to keep the hosts at bay. Three minutes to go.
85'
Hurrah! Wanyama is back on the pitch just as Forster calmly trots out to collect Iniesta's through ball towards Messi.
83'
Bad news for Celtic as Wanyama has gone down in cramp and looks to be heading off the pitch. He has been an absolute rock for his team tonight.
81'
More superb defending from Celtic as Ambrose slides in brilliantly on Messi inside the area to concede a corner. It is whipped in towards Song but Wanyama does equally well to put the former Arsenal man off.
Minute
Description
80'
Adriano gets yellow.
David Villa enters the game and replaces A. Sánchez.
Vilanova rolls the dice and brings on super-sub David Villa.
77'
Hooper is looking an increasingly lonely man in the Celtic attack, with the visitors packing 10 inside their own penalty area. And why not? They are 13 minutes away from a famous result.
76'
B. Kayal enters the game and replaces C. Mulgrew.
Cristian Tello enters the game and replaces Pedro.
75'
FORSTER AGAIN! This man is in supreme form and now pulls off probably the best save of the game, denying a point-blank Messi header after a fine scooped pass from Iniesta.
73'
Wow. If Forster was hoping to impress Roy Hodgson tonight, then he's done his job. The goalkeeper pulls off another fine save to deny Alexis inside the area. Can he keep the Spanish giants at bay?
71'
J. Mascherano gets yellow.
I tell you what, Hooper just needs one chance and Commons is trying his hardest to supply it, the latest coming from a free kick played short to the latter, who whipped in a fine cross that Mascherano cleared.
68'
WHAT A SAVE! A beautifully flowing move from Barcelona - via the boots of Alexis, Iniesta and Xavi - looks to have carved Celtic wide open with the ball drilled across for Messi to convert six yards out, but Forster pulls off a superb reaction save to deny the Argentine.
66'
Barcelona are starting to find an extra bit of space on the edge of the Celtic area as the visitors begin to tire, with Iniesta the latest to have a pop from distance. Again, Forster collects.
65'
More fine passing by Barcelona, more last-ditch defending from Celtic, but Messi manages to pull off a snap-shot from the edge of the area that Forster gathers with ease.
63'
K. Commons enters the game and replaces S. Brown.
62'
Let's see. Barcelona win a corner and Alba plays in short, only to be caught in possession by fresh introduction Commons, but the midfielder's attempted cross into the box is weak and Mascherano clears.
60'
An hour gone at Camp Nou. Can Celtic hold on?
58'
Wanyama intercepts Adriano's attempted pass to Iniesta on the edge of the area and storms forward. It is two on two with Hooper in support, but the defender tries to cut inside Mascherano and is duly stopped in his tracks. Poor decision.
55'
Barcelona again trying to work their way past Celtic, who are finding themselves pushed further and further back towards Forster. The hosts win a corner buf Xavi's delivery is plucked out of the air by the goalkeeper.
53'
CLOSE! Wow, Celtic nearly retake the lead as Mulgrew's hanging delivery to the back post is met by the head of Wanyama, but the ball bounces the wrong side of the post.
52'
Still, not to be discouraged, Forrest again skips towards the Barcelona defence and feeds Hooper on the right flank and wins a corner off Adriano...
50'
...and that is terrible. Mulgrew tries to bend the ball near post but it barely clears the knees of the Barcelona wall. Ledley picks up the rebound and somewho manages to send an even worse effort high and wide.
49'
Ooh, Celtic win a free kick near the edge of Barcelona's penalty area after a fine twisting run from Forrest. Mulgrew is standing over the ball...
48'
A less frantic start to proceedings so far with Celtic able to hold their shape further up the field after a first half which saw them spend the entire opening 45 minutes packed into their own penalty area.
46'
...and Barcelona get us back underway!
45' +2
And that's it! The half-time whistle goes at Camp Nou.
45' +1
Two minutes of added time to be played at the end of the first half.
45'
Andrés Iniesta has scored a goal for Barcelona! Assist by Xavi.
GOAL!! BARCELONA BACK IN IT! It appears I spoke too soon as the hosts level just before the break and, typically, it is a wonderful piece of football. Messi finds Iniesta with his back to goal and surrounded by defenders 15 yards out, the midfielder plays a one-two with Xavi before turning on a sixpence and slotting past Forster. All square.
44'
Barcelona, however, get the ball back straight away, and immediately start passing it in front of the sturdy Celtic defence. The hosts just cannot find a gap through though.
43'
J. Forrest enters the game and replaces G. Samaras.
A moment of relieve for Celtic as Hooper wins a free kick on the edge of his own area. Forrest has now replaced Samaras.
41'
Uh oh. This is a blow for Celtic as Samaras' ankle collapses under him as he chases for the ball. He is struggling and looks highly unlikely to continue.
39'
The tempo keeps increasing from Barcelona and Celtic are struggling more than ever with the ever-decreasing time afforded to them on the ball.
38'
CLOSE! AGAIN! Another super free-kick effort from Messi some 20 yards out as it curls away from Forster but fails to dip in time, nestling on top of the net.
36'
Brown dispossesses Messi near the halfway line and the Scottish support cheer... but the midfielder is called up for a foul three seconds later. Cue moans.
34'
Barcelona have lost only one of their last 64 home games in all competitions, at home to Real Madrid at the end of last season.
32'
Celtic are definitely frustrating Barcelona here - the Scottish side's defence holding firm against their superior opponents - but the longer this onslaught goes on, the more goals you can see coming from the hosts.
30'
Here they come again as Xavi, Iniesta, Pedro, Messi and Alexis all combine - switching the play from left to right - before the latter drills a pass across the face of Forster's goal, allowing the goalkeeper to collect.
28'
CLOSE! And it's Bartra again for Barcelona as the centre-back trots into the six-yard box and is again found by a chipped cross from Iniesta - this time his header is flashed wide, however.
26'
Barcelona are slowly going through the motions here, bit by bit turning up the tempo, but Celtic are holding on thanks to some superb defending. Adriano tears up the right flank and easily skips past a challenge from Brown before Wilson times his challenge perfectly to send the hosts back up the pitch.
24'
Celtic break again after capitalising on Song's loose pass but Hooper, darting down the right, fails to find Samaras inside as Mascherano cleans up. I think Lennon is still jumping on the touchline, and I don't blame him one bit.
22'
Barcelona win a free kick 25 yards out and Messi duly steps up. Is this the time for his 300th career goal...? No. But he was mighty close, sending the ball skimming over Forster's bar.
20'
Barcelona immediately look to retaliate through Adriano down the right flank, but again Ambrose shows a good positional sense to hoof clear.
18'
G. Samaras has scored a goal for Celtic! Assist by C. Mulgrew.
17'
CLOSE! Forster makes his first save of the match, with Iniesta's chipped cross finding Bartra six yards out - the goalkeeper pulling off an impressive reaction save... Celtic break and it's 3 on 3, but Ledley's poor pass 35 yards from goal immediately breaks down the attack.
16'
...and said movement leads to Messi and Iniesta linking up well after a short corner, but Wilson manages to clear the ball in the nick of time.
15'
Pedro has switched to the opposite flank and links up with Alba on the left as Barcelona push Celtic even deeper...
12'
Back up the other end and Alexis is back amongst the action trying to get on the end of Xavi's defence-splitting pass, but Forster rushes out and claims successfully.
11'
Celtic manage their first foray forward as Mulgrew tries to latch onto Samaras' long pass forward, but the threat is immediately nulified by Bartra. Maybe next time, lads.
9'
CLOSE! Barcelona go closest so far, with Messi feeding Alexis on the right-hand side. The forward looks for space before playing in the overlapping Alba to take over. The left-back duly swings a ball in between Forster and his defence, but Pedro can't get the vital touch.
6'
Barcelona win their first corner, which Alexis plays short to Messi. The Argentine and Song try to wriggle their way into the box via a one-two, but Ambrose hacks the ball clear.
5'
Barcelona look very menacing earlier on. If Lennon was hoping for a more relaxed showing from the Spanish giants tonight, he has already been proved wrong.
3'
...And Barcelona should be ahead with less than three minutes on the clock! Iniesta and Xavi combine well 25 yards from the edge of the area before the latter spots Alexis' diagonal run into the area. The Chilean gets his angles all wrong and guides the ball past Forster and the far post.
2'
...and Barcelona immediately have possession. This is going to be a long night for Neil Lennon & Co.
1'
And Celtic get us underway!
Good evening and welcome to Goal.com's LIVE coverage of the Champions League clash between Barcelona and Celtic. My name is Alex Young and I will be taking you through the game's events.
First things first, let's get the team news down. First up, the home side...
Here's a little stat to whet your appetite: Lionel Messi has scored 299 career goals, 268 and Barcelona and 31 for Argentina. Chance of him getting his 300th tonight? Almost certain, I'd think.
Neil Lennon makes four changes to the side that comprehensively saw off St Mirren in a 5-0 win at the weekend, but both James Forrest and Kris Commons have failed to shake off groin and hamstring injuries respectively. Scott Brown is, however, able to take his place in the starting line-up once again after passing a late fitness test on a hip problem.
We are five minutes away from kick-off now. Enough time to have a read of our match preview (written by yours truly) - just click the 'Preview' tab above this here text and have a butchers.
The teams are out, the music has finished playing. We are mere seconds away...
So, with Busquets suspended, Alex Song returns to midfield after starring in defence during the 5-4 win over Deportivo on Saturday. Youngster Bartra takes the vacant spot in defence with Dani Alves, Pique and Puyol all out injured for Barcelona.
A superb display from Celtic who defended valiantly and took their one chance when handed it. Barcelona snatched a deserved equaliser on the stroke of half-time, and I would be remiss to say I can't see them adding to their tally. Full credit, again, to the visitors' back four though.
HALF-TIME STAT ATTACK: Barcelona have attempted 475 passes, Celtic 100.
The teams are back out for the second half.
Again, absolute heartbreak for Celtic but they can be hugely proud of their performance throughout at Camp Nou. Ambrose, Wanyama and Forster the stand-out performers. Celtic stay second in Group G, with Spartak beating Benfica 2-1 in the earlier game.
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