90'+3' Game over! All three points for Barcelona.
90'+3' One last chance as Pique gets the ball from a cross. He's playing as a striker now. He holds it down and with Paulinho in support opts to go it alone. He wins a corner out of it in the end.
90'+1' Denis strikes from the rebound and Pacheco saves.
90'+1' Corner for Barcelona. goes way to long and Alaves clear.
88' Iniesta comes off for Paulinho, as the Brazilian makes his debut with Barcelona.
86' Corner for Barca. Ball lands to Alba, who strikes and it bounces up for Alexis to clear. Ely and Alexis clash heads going for the same ball and put it out for a corner. Sums up their night really.
85' Paulinho wamring up now.
83' Messi fouled as Alaves really look beaten now.
82' Rakitic and Messi link up but the chance is gone before they get a shot away.
79' Burgui wants a free but doesn't get one. Messi waits and waits for the shot but can't get it away. Alaves break and Pedraza cross is headed wide by Romero.
76' Double change. Wakaso for Enzo Zidane.Sobrino comes off for Christian Santos.
75' So, so close as Messi sees his shot come back off the crossbar.
74' Messi with a free that he clips into the box but it's headed clear by Rodrigo Ely.
Ibai Gomez replaced by Burgui.
Denis Suarez replaces Gerard Deulofeu.
72' Collision between Umtiti and Sobrino and both end up on the ground. Referee has a look but doesn't say anything. No free.
69' Romero with the shot but it-s too far away from goal to get enough on it to trouble Ter Stegen. He saves to his left and gathers it.
68' Romero buys himself a free as he steps in front of Jordi Alba and the left/back goes through the back of him. Alba livid.
66' A break by Barcelona and Alaves are 2/0 down just like that. Paco Alcacer sees his first cross blocked but it falls to Wakaso. He heads it back to Alexis and he tries pass over Alcacer-s head and he intercepts. The ball falls to Messi and he makes absolutely zero mistake. Pacheco rooted to the spot.
64' Ball lands to Jordi Alba at the back post and he drives over. Ball in from Deulofeu. The left/back in some serious pain.
62' Alba down the left again. Nothing doing this time as Vigaray gets it away.
59' Romero breaks for Alaves and Jordi Alba does well to make it back and force him to turn around. The ball into the box is lacklustre too and Umtiti with a training ground headed clearance.
57' Valverde makes a move. Aleix Vidal comes off for Paco Alcacer.
55' GOAL! Messi... Jordi Alba with the cross and Messi steps in front of Pina before he fires with his left. Deflection off Alexis and it beats Pacheco. Very unlucky but Messi with a wicked shot, as we know.
54' Deulofeu wants a free. He was hassled out of his boots by Wakaso but referee close to the action and doesn't budge.
54' Oscar Romero fouled by Iniesta.
53' Messi with a free from a perfect angle and very decent range. He swipes his left at it but doesn't really hit it cleanly. Pacheco has time to shuffle his feet across and gathers with ease.
52' Iniesta sends an inviting ball into the box and it nearly catches Pedraza out but he heads it slightly away. Strange header but effective, kind of.
51' Barcelona getting a grip on this one again.
49' Messi with a chance now. Wide.
47' Aleix Vidal looking to break free into the box but has Pedraza for company every step of the way.
46' Back underway. Ibai Gomez sends a cross low into Manu Garcia and if he was an inch longer, he'd have been able to almost tap it home.
A really enjoyable half of football that took a while to get going. We all know the issues affecting Barcelona with the board and Neymar and the lack of signings but they really look fed up. It's only two games into the season.
45'+2' Half-time. Barcelona frustrated and not looking as sprightly as Valverde might like. Changes needed, you would think.
45'+2' Zubeldia getting talked to by the ref.
45'+1' Messi clearly fouled but ref plays advantage as he continues. He clips a ball over the top and Deulofeu hits it. Pacheco gets down to his right and saves.
45' Pique reaches for a ball at the back post and handles it as blatantly as you like. He gets booked for it too.
44' They give away another corner and Alaves clear again but it's another hit and hope and Barca win it back.
44' Ball goes over everyone and lands to Messi on the volley but he doesn't make clean contact. Alaves clear and have the chance to break but their really panicking now. Need to calm down.
43' Alexis headers out for another corner.
42' Manu Garcia wipes himself off and Alaves take the free. Hanging on until half time now.
41' Sergi Roberto gets booked now. Manu Garcia might have bought that one but Roberto did come in from the back. Rash, frustrated challenge.
39' Former Real Madrid Castilla man haunts Messi. Lovely save. Nothing wrong with the penalty but a decent height for the keeper.
39' Pacheco turns Messi's penalty around the post.
38' Very, very soft penalty.
38' Let's try and make sense of this. Ball comes in and Ely pulls at Pique. Penalty.
38' Messi lines it up. Pique looking for a chilena but he was pulled down, apparently.
36' Wakaso hauls Sergi Roberto down. Late tackle deserving of a card. Quite silly from the midfielder.
36' Corner falls nicely to Pique but his strike is blocked. Alaves scramble it away. The game opening up suits Alaves to score but also to concede 10. Might not be what Zubeldia wants.
35' Game is opening up now. Deulofeu has a strike that is deflected and saved, it seems. Corner in any case.
33' Ibai Gomez with the free outside the box. Umtiti quite silly to commit a foul from there. Gomez hits the wall and Romero's shot is blocked. It lands to Gomez on the volley and he wins a corner from a deflection in the end.
32' Umtiti booked for pulling on Sibrino's shirt off the ball and then pulling him to the ground.
31' Sobrino leaves Pique for dead and is foiled by Ter Stegen one-on-one. What a chance.
30' Deulofeu looks for Rakitic. Too high for the Croatian.
27' Sobrino and Oscar Romero break. Sobrino way too slow passing it to the man ahead of him and when he does pass it, the ball is too close to Umtiti. romero with a sneaky trip on the defender.
25' Pedraza flies in and tries to win it off Messi but Messi saw him coming and turns him beautifully. Another couple of flicks and Messi has a chance to cross but not before the ball crosses the line. goal-kick for Alaves.
24' Just 70% of possession for Barcelona so far.
24' Another corner for Barcelona. Through ball by Messi to Aleix Vidal cut out this time.
23' Deulofeu plays it to Messi. Messi's left-footed shot is smothered by Pacheco.
22' Deulofeu drops the shoulder and tries to go by Vigaray but the defender gets a foot in and concedes the corner. Taken short by Iniesta. Barcelona bring it back out and try to build again.
20' The ball arrives back down their throats again. This time Wakaso tries to break but a poor pass to Romero is the result. Throw Barcelona.
20' Iniesta to Messi as the Argentine makes his way into the box but Ely wins it back and clears.
17' Alaves soaking up pressure but never been in too much trouble just yet.
17' Alfonso Pedraza very nearly gets the better of Sergi Roberto but the Barcelona man gets a foot in and gets the ball away.
16' Iniesta gets a shot away but it's not got enough pace to beat Pacheco.
13' Vidal and Sergi Roberto link well again but Barcelona lose out. Before they win it back again.
12' So, so close! Pedraza with a run forward before he has a shot. Sobrino gets a leg to it as it drifts wide but he was offside...and missed anyway!
10' Corner Barcelona.
9' Messi with a strike! Pacheco gets down to his right to save.
8' What a pass. A long ball along the ground that bends perfectly into his path as Iniesta finds Jordi Alba. The latter's squared pass is cut out but that wa ssublime from Iniesta to see the pass and then execute.
7' Messi runs out of room and he pokes it to Rakitic before he has a shot that's blocked.
5' Deulofeu with a shot that bounces in front of Pacheco. He gathers with relative ease.
4' Aleix Vidal to Sergi Roberto down the right and the midfielder launches a cross into the box. alaves clear it.
3' Really hectic start. Barcelona with the ball now. Alaves fans singing as loud as they possibly can!
2' Romero has a crack but the ref blows the whistle as Busquets is fouled in the area by a combination of players trying to block him off.
1' We are underway and Oscar Romero is fouled by Jordi Alba just outside the box. Lucky not to pick up a yelow card for that.
After a minute's silence, we are ready for action.
Valverde obviously holding out until Dembele arrives to go to the normal 4-3-3. It might be mor of a 4-3-1-2 today even. Paco Alcecer was less than convincing against Real Betis and has paid the price.
After signing Ousmane Dembele and with more signings ready to arrive, Ernesto Valverde says, "Douglas, Arda Turan and Thomas Vermaelen may leave, so let's wait and see. At the moment there are five central defenders in the team and it is possible that Marlon will also leave."
Barcelona have kept a clean sheet in their last 5 away matches against Alaves in all competitions.
Warm-up time for Alaves. It is Luis Zubeldia's first home game with the side after a 1-0 loss to Leganes at the Butarque last Friday night.
Another player to return to the fold is Gerard Pique. He missed out on the victory over Real Betis and was replaced by Javier Mascherano but is back today to shore up Barca's back line.
Barcelona have played Alaves 29 times in their history with 19 wins, 5 draws and 5 losses.
Paulinho says he has come to Barcelona to start but he has to suffice for a place on the bench to start his Barca career.
Barcelona have won their last 8 LaLiga matches and have scored at least 2 in all of those games too.
Some believe that it is a 4-3-3 with Andres Iniesta set to occupy the last attacking spot alongside Deulofeu and Lionel Messi.
No Burgui in Alaves' team to start today either. Enzo Zidane also on the bench for Zubeldia's side.
Unclear as to what formation Barcelona will use but it looks like it might be a 4-4-2 or some variation? Hard to know as Deulofeu and Messi are the only two attacking players in the team. Sergi Roberto could also help out as a versatile threat but he's not what you would call an attacker? Rakitic might be another one who could add something going forward.
Barcelona team news: Ter Stegen, Aleix Vidal, Piqué, Umtiti, Alba, Busquets, Iniesta, Rakitic, Sergi Roberto, Messi, Deulofeu.