Barça beat Celta thanks to Messi's 52nd career hat-trick
Barcelona vs Celta Vigo: as it happened!
Two minutes of added time.
Into the last minute. Celta's challenge, which hasn't been bad, has petered out.
Ter Stegen with the save but he puts it out for a corner.
Busquets gets a yellow card. Free for Celta Vigo on the edge of the penalty area.
BUSQUETS! He strikes from distance and it finds its way home. Nice move from De Jong to start the play.
Toro Fernandez saved by the offside flag. He misses a one-on-one but it gets called back for an offside.
Suárez with the strike. He rounds a defender with ease and then strikes it wide.
Celta Vigo sub. Pape Cheikh come of for Toro Fernandez.
Aidoo goes toe to toe with Dembele and wins it in a race as Suárez sends it over the top. He concedes the throw though.
Hugo Mallo slides in and kicks the ball off Firpo to prevent a dangerous attack and also to prevent the corner.
Lobotka off for Denis Suárez on his return to the Camp Nou.
Sergi Roberto with the cross into the box and it nearly turns into a shot. Nearly dips home but not quite.
Griezmann off for Suárez.
Messi looking for his fourth. Dembele delivers a lovely ball across the box. Messi slides in and can't connect with it.
Messi to Griezmann and Griezmann plays it back. Messi gets thrown out of the way and the Camp Nou wants a penalty. They might have a point too but referee says no.
Roberto with the pass to Dembele, who is steaming forward, but it's just behind him. Barcelona keep it and attack again. Brais with the foul on Arthur.
Aspas clipped and turned upside down as he wins a free.
Sisto off for Brais Mendez.
Messi with the pass for Griezmann and he fires it straight into the goalkeeper's chest.
Luis Suárez warming up.
Umtiti needs to be careulf. He catches Aspas from behind and concedes the free. He's already on a yellow. Barcelona, aside from Messi's brilliance, have been very average.
A nice spell of possession ends with a cross that's too tall for Mallo.
Sisto with a shot from a really right angle and he can only aim it straight at him. Nice run forward but he was isolated and Ter Stegen not troubled.
Celta playing well and Fran has an effort now that Ter Stegen has to save!
And now Sergi Roberto catches Junca. He gets booked.
Celta counter and Fran plays to Sisto. He aims it at Ter Stegen but it's hand enough for him.
Messi with another free. He can't, can he?
Dembele with almost the most incredible start. First touch results in a mazy run and he curls one over the bar. What an introduction that is.
We are back underway for the second half!
Dembélé off for Ansu Fati at the break.
Messi and Griezmann haven't connected with a single pass in the first half according to Opta.
HALF-TIME! That's an incredible way to end the half.
Fran gets booked for pulling back Arthur. He failed but gives away the free anyway.
Dembélé is warming up here.
GOAL! GOAL! GOAL! Lucas Olaza with the golazo from the free. Up and over the wall and leaves Ter Stegen with no chance.
Messi gives the free away as he wins the ball and the ref says it was foul. He is booked too for that. Bizarre decision from the referee.
It's a goalkick. Barcelona have the ball in the net but Arthur overran it. Messi was the one who finished but quite obviously, it's out over the line.
Celta's good start is petering out now.
Messi with a left-footed effort now as Rubén rejects him again.
Pape Cheikh gets a kick on the leg from Sergi Roberto. No card this time.
Ter Stegen wants to take the kick-out quickly but the referee tells him to wait for the whistle.
Aspas with the shot. That's just wide.
Umtiti booked now as he hauls down Pape Cheikh.
A lot going on there. Semedo is forced to go off for Busquets.
PENALTY! Aidoo with the handballon a Semedo cross. Fairly standard as his arm was up in the air. VAR checking but can't see how it's overturned.
Long ball launched in to Ansu Fati. The kid is fast but not that fast.
First sighting of Messi and he drives a low show that is saved by Rubén.
Celta win a free for a handball by Semedo and it gets whipped in but Ter Stegen is as safe as houses with the grab as it bounces in front of him.
Ball ends up out for a goalkick.
Barcelona getting into this now. Firpo with a nice move as he passes to Arthur.
Cheikh fouled by De Jong as Celta attack again. Barcelona haven't really started this one yet.
Ball from Griezmann to Ansu Fati but Aidoo muscles him out of it and sees it out for a corner.
Griezmann playing through the middle and gets bundled over as he receives the ball.
Hugo Mallo gets it from Sisto way out on the right. He crosses and it's another throw. Celta have looked decent here. Only five minutes but still.
Pape Cheikh with a nice move and get it to Aspas. He plays it to Lobotka and Celta attack. A little too slow though as Aspas eventually gets it back and wins a throw.
Barcelona being pinned back by Celta. No way through yet as Celta almost intercept and send it back to Ter Stegen. He picks it up and assesses his options.
Celta Vigo with a nice spell again as Rubén ends up launching forward. Barcelona win it back.
Celta Vigo on the ball for the irst time and they try to play expansively before launching it forward.
Semedo on the receiving end of an early challenge and gets a free.
We are underway at Camp Nou!
Fran Beltrán says he would have to consider his options if he didn't start more games for Celta. He starts again tonight so let's see if his career kicks off now with a new manager. Denis Suárez has been a surprise exclusion though as Sisto comes in.
Barcelona have not lost any of their seven games with Sergio Busquets in the starting XI this season. 6 wins and one draw.They have lose three of the four without him.
Celta Vigo XI: Rubén, Mallo, Aidoo, Araujo, Olaza, Lobotka, Beltrán, Pape Cheikh, Juncá, sisto, Iago Aspas.
Barcelona XI: Ter Stegen, Semedo, Piqué, Arthur, Messi, Griezmann, Roberto, De Jong, Umtiti, Junior Firpo, Ansu Fati.
Following Real Madrid's big win over Eibar, Barça fans will expect nothing less than all three points to take them back to the summit of the Spanish league.
Hello and welcome to our live coverage as Barcelona welcome Celta Vigo to the Camp Nou. Kick off is at 21:00 CET and we're already building up to it.