FULL-TIME: Celtic 2 Barcelona. Celtic have done it as they record a famous win over Barcelona thanks to goals from Wanyama and Watt with Messi netting a late consolation for Barcelona.
Celtic win a goal-kick and they are so close to a famous win.
Mulgrew makes two vital clearances as Barcelona pile forward.
GOAL: Barcelona pull a goal back as Messi scores from close-range after Forster can only push Villa's shot into the path of the Barcelona ace.
There will be four minutes of added time at the end of the 90 minutes.
Iniesta tries his luck with a shot from the edge of the box, but Forster is equal to it again.
Watt almost gets in on goal again but he goes down under pressure from Mascherano, but the referee waves away Celtic's appeals for a free-kick and what would have been a certain red card.
GOAL - Tony Watt - Parkhead goes crazy as Watt is sent clear and fires home the second, unbelievable scenes!
Kayal replaces Celtic captain for the night Samaras in the home side's second change of the game.
Xavi tees up Villa on the edge of the box, but his effort flies over the crossbar.
Alba's volley is blocked by Commons for another Barcelona corner as the visitors pour forward.
Iniesta works from space on the edge of the box to line up a shot, but he drills it well over the top.
Samaras is lucky to win a free-kick on the edge of his own box as he takes too long to clear his lines.
The impressive Matthews makes another good tackle on Alves to break up another Barcelona attack.
Celtic make their first change of the game as Tony Watt comes on for Lustig meaning Ambrose shifts to right-back and Mulgrew drops into central defence alongside Wilson.
Double change for Barcelona as Pique replaces Bartra and Cesc Fabregas comes on for Song.
Another fantastic save from Forster as he dives full stretch to keep out Messi's shot after Alba picked him out inside the box.
Barcelona win a corner as Commons turns Alves' cross behind.The pressure is building.
Song is lucky to be still on the pitch as already on a booking he fouls Miku. The midfielder is playing with fire lucky escape for Barcelona.
Alba is booked for a foul on Commons.
Barcelona make their first change of the game as David Villa comes on for Sanchez.
Wasteful from Wanyama as he gets into the box, only to drive his cross over the top.
Massive chance for Celtic as Bartra misjudges a long ball into the box allowing Mulgrew to get on the end of it, but the defender gets back to block his goalbound effort.
Great double save from Forster as he gets down low to save Sachez's initial shot before getting back to his feet quickly to keep out his follow up effort with his legs
Forster does well as he races his line to prevent the ball going behind for a corner to ease the pressure for Celtic.
Commons works the corner to Mulgrew who crosses for Lustig to head weakily at Valdes.
Celtic have a bit of pressure as Mulgrew wins a corner off Alves.
Messi works some space on the edge of the box before curling a shot towards the top corner that is well saved by Forster.
Mulgrew robs the ball from Messi and sets off a run towards goal before being blocked by the Barcelona defence.
Matthews makes a vital last-ditch tackle to deny Messi getting in on goal from Alves' pass.
Good defending from Ambrose as Barcelona start to put some crosses into the box.
Good tackle from Matthews to deny Alves at the expense of a corner.
Difficult header for Pedro from Alves's cross and his effort fails to trouble Forster.
Alves finds space down the right, but his cross is poor and is runs out of play.
Alves's fires in a deflected shot which is gathered by Forster at his front post.
Mascherano tries to seek out Pedro with a long through-ball, but his pass is overhit and runs out of play.
RESTART: Celtic get the second half underway with no changes from either side.
HALF-TIME: Celtic 1 Barcelona. The referee brings the first half to a close with Wanyama's goal the difference between the two sides. Barcelona have struck the woodwork twice as they push for an equaliser.
A mix-up between Iniesta and Alba sees them lose the ball and give Celtic a throw-in.
Great block from Commons to keep out Iniesta's shot.
Miku is booked for a late tackle on Iniesta.
Forster does just enough to stop Messi getting on the end of Alba's cross.
Xavi almost puts Alves in on goal, but his pass is just overhit and it runs out of a play for a goalkick.
Wilson is given a ticking off by the referee after a heavy challenge on Pedro.
Mascherano makes a vital last-ditch tackle on Miku to deny the Celtic striker getting in on goal from Mulgrew's cross.
Barcelona go so close again to equalising as Alves sends over a cross from the right and Sanchez is unlucky to see his header come back off the post.
Lovely move from Barcelona as Sanchez plays in Alba, but there is no one in the six-yard box to convert his inviting cross to the relief of the Celtic defence.
Alves tees Xavi on the edge of the box, but the midfielder drives his shot over the crossbar.
Barcelona dominating possession as they probe for an opening, but so far the Celtic defence holding tight.
30 mins gone and it is Celtic 1 Barcelona 0 and the home fans are dreaming of a famous win.
Barcelona inches away from equalising as Messi fires in a shot which clips the top of the crossbar.
Alba's cross is headed back across goal by Alves, but Celtic manage to clear.
Good attack from Celtic as Matthews gets in down the left, but his cross towards Samaras is just too close to Valdes who collects the ball.
Alves's shot from the edge of the box is deflected over by Mulgrew for a Barcelona corner.
Iniesta fires in a shot with his left-foot which is blocked by Wilson. All hands to the pump now for Celtic.
Barcelona are trying to respond now, but Commons manages to clear the danger.
GOAL: Wanyama heads home Mulgrew's corner to send the home fans into raptures. Poor defending from Barcelona as Wanyama rises above Alba to head home past Valdes.
Wanyama is all over the pitch as he tries to get Celtic going and the home fans appreciate his effort. Celtic win their first corner of the game.
Song brings down Miku and he is walking a tightrope as he is already on a booking.
Good tackle from Lustig, but he appears to have picked up a knock in the sliding challenge.
Good tackle from Ambrose on Messi inside the box to rob the Barcelona ace of the ball. The pressure is building on the home side.
15 minutes gone and it remains 0-0 and Celtic will be happy with the start so far.
Matthews' long throw is punched clear by Valdes before Celtic are caught offside as the ball comes back into the box.
Song is the first player to be booking for tugging back Miku.
Good play from Wanyama in the middle of the pitch to rob Iniesta of the ball. Celtic will need to do a lot of that tonight.
Commons makes another late tackle this time on Song, but the midfielder escapes a booking.
Forster is quickly off his line to prevent Sanchez getting on the end of Pedro's pass.
Messi wastes a great chance to open the scoring after beeing teed up by Alba, but the Argentine drives his shot over the crossbar. A warning sign for Celtic.
Sanchez has the first effort on target, but his flick is comfortably saved by Forster.
Commons is given a ticking off by the referee for a late tackle on Iniesta.
Celtic win a free-kick as Samaras is fouled by Mascherano. Chance for Celtic to get a ball into the box, but Mulgrew plays it short before firing in a cross which is cleared by Song.
Wanyama puts in a good tackle to deny Sanchez and Willson then keeps out Pedro as Celtic win a goalkick.
Samaras is leading the link for Celtic with Miku playing the support role dropping deep to help the midfield.
Barcelona quickly into their stride as they look to take the game to Celtic.
Kick-off: Barcelona get the game underway at an expectant Parkhead.
The two teams emerge from the tunnel to a wall of noise.
Danny Burns can't see Celtic scoring and expects Barcelona to win 3-0.
You'll Never Walk Alone is belted out by the home fans as we get close to kick-off.
Aidan Pidgeon is expecting an emotional night at Parkhead and is hoping for a 2-1 win to Celtic.
Nevam Higgins thinks the Barcelona defence looks weak and expects Celtic to score and he is going for a 2-2 draw.
Akshet Shetty would love to see Celtic come away with a win, but is predicting a 2-0 win for Barcelona. What do you think the score wil be?
Gerard Pique has been added to Barcelona's squad after returning from a foot injury but he started on the bench although the Catalan giants paraded their big guns, Lionel Messi, Andres Iniesta and Xavi Hernandez
You can get in touch with your thoughts, predictions, opinions and jokes (within reason) throughout the course of the evening and I will do my best to publish those that make me think or laugh. Contact me at peter.O'Rourke@bskyb.com or via twitter @SkySportsPeteo
Shahbaz Ahmed is expecting Barcelona to teach Celtic a lesson feeling it will be an easy win for the Spanish titans. What do you think?
Barcelona starting XI: Victor Valdes; Daniel Alves, Marc Bartra, Javier Mascherano, Jordi Alba; Xavi, Alex Song, Andres Iniesta; Alexis Sanchez, Lionel Messi, Pedro
Celtic starting XI: Fraser Forster; Mikael Lustig, Kelvin Wilson, Efe Ambrose, Adam Matthews; Kris Commons, Victor Wanyama, Joe Ledley, Charlie Mulgrew; Giorgos Samaras, Miku
Gerry Cassidy in Christchurch New Zealand is hoping Celtic can take something from the game after going so close two weeks at Camp Nou
If you would like to get in contact at any point this evening 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
Giorgios Samaras, though, is fit after recovering from an ankle problem and Miku will start in attack in place of Hooper.
Some breaking team news as Gary Hooper misses out for Celtic through injury and Scott Brown is sidelined with a virus
Welcome to our minute-by-minute commentary of Celtic's Champions League game against Benfica from Celtic Park.
Kick-off is 1945 GMT.