90+4 Last chance for Celtic as they pump a free-kick into the box, but Barcelona clear the ball and the referee brings the game to a close and it ends 1-0 to Barcelona thanks to Fabregas' header with Scott Brown seeing red for Celtic.
Neymar is played in on goal by Alexis, but Forster produces another brilliant save to keep out his effort.
There will be four minutes of added time at the end of the 90 minutes.
90 Alexis is booked for a late tackle on Samaras.
89 Iniesta comes off for Song in Barcelona's final change of the game.
Brilliant double save to keep out Neymar's first shot and then getting back to his feet quickly to block Alexis's follow-up effort.
86 Celtic make their final change of the game as Pukki comes on for Commons.
86 Izaguirre is booked for a late tackle on Bartra.
Samaras gets in down the right, but his cross is poor and is easily cleared by Barcelona.
Barcelona just keeping hold of the ball as they to find an opening.
Matthews is forced to concede a corner to stop Neymar getting on the end of Alves' cross.
Neymar tries to find Alexis inside the box, but Forster is able to collect the cross before the striker.
Into the final ten minutes now and it is going to take something special for Celtic to get back into this game.
Vital interception from Matthews to cut out Neymar's intended pass towards Alexis.
78 Barcelona make another change as Fabregas is replaced by Tello.
77 Samaras is now booked for Celtic for a late challenge on Busquets.
76 GOAL: Celtic 0 Barcelona 1: Fabregas breaks the deadlock as Alexis breaks down the right and picks out Fabregas who plants his header into the net past Forster.
75 Busquets is the latest player to be booked after a nasty challenge on Kayal.
74 Barcelona make a change as Alexis Sanchez comes on Pedro.
From the resulting corner Celtic should score as Valdes is caught in no man's land, but Mulgrew heads his effort wide of the target with the goal at his mercy.
Great save from Valdes as he throws himself to keep out Forrest's half-volley from 12 yards.
Neymar works a one-two with Xavi inside the box, but he can't get his foot sorted out quickly enough and he hits his shot well wide of the target.
20 minutes left and it remains 0-0 but Barcelona have the advantage with Brown being sen off for Celtic.
69 Double change from Celtic as Forrest comes on for Lustig and Kayal replaces Stokes to stiffen up the midfield.
Fabregas's cross is poor and it goes straight into the arms of Forster with Barcelona having players in the box.
Neymar claims for a penalty as his cross is blocked inside the box, but the referee waves away the Brazilian's appeals.
Great defending from Samaras as he cuts out a pass from Iniesta to lift the home crowd.
Forster is called into the action to get down to Bartra's shot from the edge of the box.
Neymar is brought down by Ambrose as Barcelona look to make their numerical advantage count.
Samaras wins a free-kick off Busquets and Mulgrew will take the free-kick and his Valdes comes flying out of his goal to take the cross, but he misses it and is lucky to see it fly out of play.
It looks like Neil Lennon is preparing a tactical change as a result of Brown's sending off.
Neymar is public enemy no.1 for the Celtic fans as they feel he overplayed Brown's kick out at him.
Celtic up against it now, but Xavi's resulting free-kick is poor and is runs straight out of play.
59 Scott Brown is sent off after appearing to kick out on Neymar after bringing down the Brazilian in full flow.
Decent spell for Celtic as Pique cuts out a cross from the left from Commons towards Stokes.
Alert defending from Pique as Busquets poor header back towards Valdes is read by Stokes, but Pique gets back to cut out the danger.
Things getting a bit scrappy now and Alves is rolling around and is in need of treatment after falling awkwardly, but the full-back looks like he will be okay to continue.
55 Fabregas is booked for a late tackle on Stokes even though it looked like the former Arsenal man got the ball in his tackle.
Xavi fires in a shot from the edge of the box, but his effort is well blocked by van Dijk.
Good defending from Bartra as he robs the ball off Samaras down the left.
Brown has a sight of goal, but he slices his shot well wide of the target. Rare opening for the home side.
Poor pass from Fabregas as he gives the ball away to Brown to ease the pressure on Celtic.
Alves is down and in need of treatment after being caught in the face by Izaguirre, but the Brazilian is ok to continue.
More good defending from Ambrose to rob Neymar of the ball inside the box after the Brazilian showed some dancing feet.
The pattern has continued with Barcelona hogging the ball and Celtic happy to defend deep.
RESTART: Celtic get the second half underway with both sides unchanged.
45 The referee brings the first half to a close and the two sides go in at the break all square and Celtic will be happy with that after the opening 45 minutes.
Xavi's resulting free-kick is just about cleared by Forster for a corner.
44 Lustig is booked for bringing down Neymar wide on the left.
Unlucky from Iniesta as he works a one-two with Neymar, but his touch is too heavy and the ball runs out of play.
Celtic struggling to get out of their own half with Barcelona stepping up the pressure.
Barcelona's best chance so far as Alves' whipped cross is diverted just wide of the target by Neymar inside the box.
Izaguirre is a little wasteful as he overhits his pass towards Commons and the ball runs out of play.
Strong run down the right from Matthews and just as he tries to cross the ball it comes off his other foot and runs out of play.
Poor from Lustig as he gives the ball away with Celtic finding themselves in a good position down the right.
Neymar is finally back on the pitch after lengthy treatment, but he looks a little shaken up.
Barcelona still probing and looking for an opening, but they are playing with ten men as Neymar is off the pitch receiving treatment.
Neymar is down and in need of treatment after a good hard challenge from Izaguirre.
Two misplaced passes by Xavi in the same game - that doesn't happen very often!
Neymar has swapped positions to the right-hand side and he fires over a cross which Ambrose clears.
Half an hour gone and it remains 0-0, but Barcelona are continuing to knock at the door.
Some relief for Celtic as Iniesta's cross is overhit and goes out of play for a goalkick.
Vital interception from Ambrose to stop Iniesta's pass finding Neymar in behind him.
Good defending from van Dijk to stop Pedro getting on the end of Fabregas' through-ball.
Neymar feeds in Neymar down the left, but under pressure from Ambrose he fires his shot into the side-netting.
Neymar is given a ticking off by the referee after going down too easily in a bid to get a free-kick on the edge of the box.
Good tracking back from Commons as he gets back to stop Neymar's pass finding its ways to Alves.
Iniesta is caught offside as he tries to race clear on goal.
Good defending from Izaguirre as he blocks out an intended cross from Pedro.
Misplaced pass from Xavi gifts it straight to Samaras, but his cross goes straight into the arms of Valdes.
Iniesta finds space on the edge of the box and lets fly, but his shot is well over the top.
Ambrose is late on Busquets, but the referee only gives hima ticking off when it could have been a booking for the defender.
Neymar comes in from the left and beats a couple of challenges, but he drags his shot wide of the target.
Fabregas has a sight of goal, but his scuffed shot is cleared by Ambrose.
The possession stats show Barcelona have had 79% of the ball in the opening 15 minutes.
van Dijk adjudged to have fouled a Barcelona player in the box from the free-kick from Mulgrew and Barcelona win a free-kick.
Samaras wins a free-kick in a good position for Celtic to deliver a ball into the box.
Ambrose gets a vital touch in to stop Fabregas finding Pedro inside the box.
Great tackle from Lustig on Neymar as Barcelona win another corner, but Celtic clear the danger.
Barcelona in their usual style closing down Celtic in packs when they have the ball.
Ten minutes gone and Celtic will be happy with the start they have made so far.
Commons has a sight of goal, but Busquets gets in a great block to keep the shot out.
Great atmosphere in Celtic Park with the home fans making a great noise.
The referee Stephane Lannoy spots an infringement in the penalty area as Mulgrew curls in the corner and awards Barcelona a free-kick.
Great move from Celtic as Stokes slips Samaras inside the box, but Valdes is out quickly to keep out his shot from a tight angle as Celtic win their first corner of the game.
The corner is cleared and drops to Alves on the edge of the box who sees his fly wildly over the crossbar.
Lovely skill from Iniesta as he nutmegs Ambrose, but van Dijk is on the cover to clear the danger for a corner.
The corner comes in and it is cleared by van Dijk and finally Celtic have a feel of the ball.
Iniesta tries to pick out Neymar, but Ambrose gets his head to the ball to concede an early corner.
Nice early glimpse of what Neymar has to offer as he skips past Lustig as Barcelona not suprisingly dominating possession.
KICK-OFF: Barcelona get the game underway at a nosiy Celtic Park.
What are your predictions?
Chris Green from Huddersfield is hoping Celtic can pull off another shock, but his head tells him Barcelona to win 3-0.
Sean McAllister believes the loss of Messi gives Celtic a major boost as they look to pull off another win over Barcelona.
Rod Stewart was in tears after last season's win over Barcelona. I wonder what famous faces will be in the crowd this team.
It will be interesting to see how Neymar fares tonight with more onus on him in the absence of Messi.
The atmosphere is growing at Celtic Park as we get ever closer to kick-off.
Celtic have won only one of their six Champions League games against Barcelona (1 draw, 4 defeats). That solitary win came in last season's group stages at Celtic Park.
Barcelona have only won 2 of their last 8 Champions League games away from home (2 draws, 4 defeats).
Celtic have only suffered 3 defeats in 24 Champions League home games, but 2 of these were against Barcelona.
Some stats for you all from our friends at Opta ahead of the game..
How big a blow will the loss of Lionel Messi be for Barcelona?
The two goalscorers for Celtic in last season's game are not involved in this game with Victor Wanyama sold to Southampton and Tony Watt loaned out to Belgium.
Who are they key men for both sides?
What are your score predictions?
Can Celtic repeat their famous win over Barcelona after beating the Spanish giants 2-1 last season?
Feel free to air your opinions throughout the game. You can contact me direct at Peter.O'Rourke@bskyb.com, or Tweet me @skysportspeteo.
If you would like to get in contact at any point this afternoon then please don't hesitate. You can mail me via the Score Centre, email me direct on email@example.com and you can also now Tweet me: @skysportspeteo.
If you fancy a flutter on tonight's game, why no visit our friends at SkyBet for a little flutter. Celtic 7/1 Draw 4/1 Barcelona 2/5.
Celtic XI v Barcelona: Forster; Lustig, Ambrose, Van Dijk, Izaguirre; Matthews, Brown, Mulgrew, Samaras; Commons; Stokes.
Barcelona XI v Celtic: Valdes, Alves, Bartra, Pique, Adriano, Sergio, Xavi, Iniesta, Neymar, Cesc, Pedro.
The teams are in...
Welcome to our minute-by-minute commentary of Celtic's Champions League clash against Barcelona from Celtic Park.