SUBSTITUTIONpublished at 67 mins
Life isn't too bad for Barcelona, 5-0 up and able to bring on one of the best midfielders of this generation. Andres Iniesta replaces Sergi Roberto and takes the armband from Lionel Messi.
Messi runs from centre circle for opener; Neymar scores brilliant chip
Messi cuts in from right for his second
Barca go back to top with win
First game since Luis Enrique announced he will leave this summer
Emlyn Begley
Life isn't too bad for Barcelona, 5-0 up and able to bring on one of the best midfielders of this generation. Andres Iniesta replaces Sergi Roberto and takes the armband from Lionel Messi.
Celta Vigo haven't had many chances but they've messed up the few they've had. Iago Aspas finds Daniel Wass in plenty of space 15 yards out. But the Dane fires well wide under no pressure. Poor.
Lionel Messi
Moments after that Iago Aspas slip, Barcelona have the ball in the net and it's Lionel Messi's second.
He gets the ball on the right, cuts inside past two defenders and nutmegs one while finding a bottom corner of the net. Keeper Sergio Alvarez is rooted to the spot.
Celta Vigo striker Iago Aspas goes past a defender and slips...
Celta Vigo striker John Guidetti comes off, he doesn't look too happy with what has happened today. On comes Jozabed, who is on loan from Fulham.
Samuel Umtiti
It's a rout. Lionel Messi plays the ball across the box and Barcelona centre-back Samuel Umtiti turns it past the keeper from six yards out.
That's his first goal for Barcelona.
On comes Javier Mascherano for Sergio Busquets in midfield for Barcelona.
Ivan Rakitic
This scoreline probably mirrors the dominance more. This could end up being 5-0 to 6-0.
Neymar takes on a Celta defender, cuts it back to Lionel Messi, who finds Rafinha. His touch lands to Ivan Rakitic, who is probably just about offside, and he slots home.
Game over.
Lionel Messi tries to find a team-mate in the box but a Celta Vigo defenders just hoofs it clear. This could be a long 35 minutes for the visitors.
Celta Vigo make a change as Pione Sisto replaces fellow winger Theo Bongonda.
Even Barcelona's defenders are getting involved up front.
Sergi Roberto, who is a right-back, goes on a mazy run and is narrowly denied a third goal for Barcelona.
And then seconds later Lionel Messi clips a ball over the top to Gerard Pique. The centre-back controls it on his chest and then tries to side-step a Celta player before shooting. It doesn't go well.
Celta Vigo have their third player booked as Sergi Gomez brings down Neymar.
Celta Vigo have an early free-kick but Gerard Pique heads Iago Aspas' cross out of the mixer.
The second half is under way at the Nou Camp. More of the same please.
In a day when my team lost against promotion rivals, all my bets failed and my fantasy football team were basically trolling me, that first-half performance from Barcelona has really cheered me up.
#bbceurofooty
Dave Wood: Party time at the Camp Nou
Andrew Reyes: Best 45 mins Barca have played for a long time. Perhaps there is a small chance to overturn the four-goal deficit vs PSG
If I could use emojis in a live text, it would be that one with the love hearts in the eyes.
Oh look, I've worked out how...
Barcelona 2-0 Celta Vigo
Barcelona lead 2-0 at the break thanks to two excellent goals in a swashbuckling performance. At times they have looked like the Barca of old.
Luis Suarez is the only one of Barcelona's front three not to score yet. If they keep playing like this, they will get more in the second half, and he will fancy his chances of netting.
#bbceurofooty
Messi's left boot: Barca need the Messiah to be at his very best for the match against PSG. Can you coach the likes of his talent?
If they play like this, Barca are entirely capable of beating PSG by four or more goals to go through.