We're going to wrap this live up now, but here's the match report for you to read.
Thanks for joining me today, see you soon.
Another league with a tasty title race brewing is Ligue 1. After wins for Paris St-Germain (1-0 v Nancy) and Nice (1-0 at Dijon) today, it's a three-way tie at the top.
Monaco - who host Nantes tomorrow - lead on goal difference from PSG and Nice.
We are in for a thrilling title race hopefully in La Liga. Barcelona are one point above Real Madrid, who have a game in hand following their World Club Cup exploits in December.
Sevilla, who go to Alaves on Monday, are still in the mix too. They will be two points off Barca if they win that.
Clear your diaries for the weekend of 22-23 April by the way - that's when Real Madrid host Barca in what could be a huge match.
Barcelona return to the top of La Liga with one of the performances of the season. They have absolutely destroyed Celta Vigo - it was 5-0, it could have been 8-0.
Can't fault his ambition. Iago Aspas has a go from 50 yards but it's easily saved.
Celta Vigo striker Iago Aspas takes on three Barca defenders... and then fires wide. It's not been his night.
Three minutes added on.
Very nearly a sixth as Lionel Messi plays a one-two with Luis Suarez before crossing to Denis Suarez, but his header is straight at the keeper.
Another sensational spell of passing, with Lionel Messi involved three or four times, eventually ends up in a goal kick. Is this the performance of the champions?
We've seen a million replays of Ivan Rakitic's goal. He was definitely offside, but in the grand scheme of things, this would still have been a comfortable win without it.
Alonso: Luis Enrique could be the first manager in history to begin and end his tenure with a treble. Still not good enough eh?
Close to a sixth as Luis Suarez holds off a challenge or three and plays a one-two with Rafinha, but his shot is all the way across the keeper and the goal, with Denis Suarez unable to turn it home.
Celta Vigo have a free-kick but Iago Aspas fires well over. If this was the only Celta game Liverpool fans have seen this season, I'm not sure they'd believe that he is genuinely a good striker.
There's 12 minutes to go now, but the game has calmed down a bit. Barcelona are still in control but they're down to third gear now maybe.
Lionel Messi is in on goal, is it time for his 38th hat-trick for Barcelona? No, instead he tries to square it to Luis Suarez, who hasn't scored today, but a Celta defender intercepts it.
Gerard Hennessy: Luis Enrique - what a failure as Barca coach! Only won the treble in his first season and the double in his second. And third??
Denis Suarez finds his brother Luis (they're not really related) but the Uruguayan is offside.
This is the first time all season that Lionel Messi has had a hand in four goals in a La Liga game - two goals and two assists.
Prince Gyimah: Someone should tell Luis Enrique and his Barca team to reserve some of the goals for PSG
Honestly, if they play like this again they will beat PSG by four or five
Neymar comes off to a standing ovation after his luscious lob earlier. Denis Suarez is the man to replace him.
Celta Vigo bring on Marcelo Díaz for Daniel Wass.
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.
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.
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.
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.
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.
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 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.
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.