The hosts will surely have to come out and chase this game, with Koeman perhaps looking to the likes of the in-form Braithwaite or Coutinho off the bench. For the Italians, Pirlo will simply be asking for more of the same from his side, who constantly look dangerous on the counter-attack as the hosts commit more and more men forward.
Pirlo's side profited from a lightning start as Ronaldo opened the scoring from the penalty spot, after being brought down by Araujo inside the area. McKennie then doubled the visitors' lead with an impressive, acrobatic finish, courtesy of Cuadrado's good work down the right. Koeman's men then enjoyed sustained spells of possession but rarely threatened Buffon's goal, which is why Juventus go in 2-0 up at half-time.
45' + 3' HALF-TIME: BARCELONA 0-2 JUVENTUS
45' + 2' Messi manages to get a shot away inside the area but appears to have been dragged down by McKennie in his attempts to do so. Play goes on while VAR has a look at the decision before agreeing with the referee and giving nothing.
45' + 1' There will be two minutes of added time as the visitors still appear content to sit on the edge of their own area and aim to counter-attack when the hosts slip up.
45' Trincao plays in Dest towards the byline on the right and the full-back drives a good cross across the face of goal, however, no one in a Barcelona shirt is there to meet the pass.
44' Cuadrado has his arms in the air as he feels the referee was too hasty in awarding the hosts a free-kick wide on the right. Koeman's side take it quickly before Messi is crowded out on the edge of the area by McKennie and Bonnuci.
43' Pjanic rather unselfishly opts to pass rather than shoot, sliding in Dest to the right of him inside the area. The right-back can then only place a right-footed effort wide of Buffon's goal under little pressure. He will feel he should be doing better from that sort of position.
41' Messi and Trincao combine down the right with relative joy before the former cuts in on his favoured left foot but a wall of Juventus shirts greet the shot to block it away from danger.
40' Cuadrado goes flying down the right and slots in Morata, Araujo again does remarkably well to manage the striker's run and intervene without giving away a corner.
39' Morata runs straight through the centre of the pitch and is found by Danilo, however, Araujo does well as the last defender to intercept and play backwards towards Ter Stegen.
37' Juventus are camped on the edge of the area but Koeman's side cannot play through them. Morata then rushes away down the left before sensibly opting to play backwards and retain possession, giving his side a deserved break from defending.
36' CHANCE! Alba is slid in by Messi out wide and immediately looks to return the favour towards the hosts' captain. Messi runs onto the return pass before his left-footed effort is saved well by Buffon moving to his right in goal.
35' The hosts are insistent on pressing high and they are winning the ball back in good areas. However, every time Juventus break the press it looks like there will be a chance. This time, Ronaldo and Morata attempt to counter-attack before the former's pass is cut out by Araujo.
34' Dest does well against two Juventus players to work the ball back inside. The hosts then play out towards the left before Alba loses posession and the move breaks down.
32' Messi is fouled near the centre circle as fouls appear to have taken over this game in the last ten minutes or so. Pirlo and his men will be delighted either way as, at this rate, they only need one more goal to qualify as winners of Group G.
30' Messi plays the simplest of passes to tee up Pjanic but the midfielder can only drive his right-foooted effort wide to the left of Buffon from the edge of the area.
28' Ramsey has the chance to slide in Ronaldo through the middle, however, his attempts to volley are poor and then the Welsh midfielder clatters into Lenglet in the air. The hosts do not appear best pleased as that is Ramsey's second foul in three minutes.
25' CHANCE! Juventus create a chance down the other wing this time as Alex Sandro whips in a left-footed cross. Morata meets the wing-back's ball in, but his flicked header at the near post sails just over Ter Stegen's goal.
24' Cuadrado and Morata both attempt to cross into Barcelona's area and the latter's attempt looks to smash into Pjanic's hands, however, the referee disagrees and insists play goes on.
22' SAVE! Messi takes matter into his own hands, driving in from the left before drilling a low left-footed effort from 20 yards out. Buffon is more than capable of responding to Messi's effort as he gets down well, diving to his left to tip the shot around the post.
20' Dest makes his side's poor start even worse as he produces a foul throw on the right-hand touchline to gift possession back to the visitors. Alex Sandro is then extremely fortunate to keep the ball as he is swarmed by four Barcelona shirts on the left.
18' The hosts manipulate possession from side to side for a couple of minutes, with both Messi and Dest attempting to penetrate Juventus' three-man defence out wide. Pirlo's men defend well and eventually regain possession inside their own half.
16' Cuadrado is in acres of space wide on the right, which Morata acknowledges with a long pass. However, his right-footed diagonal pass is way off target and trickles out near the halfway line for a Barcelona throw-in.
15' Morata looks to be in on goal after Ramsey's curling pass but Araujo does well to get his body between the striker and the ball as Ter Stegen sweeps up the danger.
14' Ronaldo has scored 16 goals in his last 21 appearances versus Barcelona in all competitions, including netting in two of his last three games against them while with Real Madrid.
12' PENALTY TO JUVENTUS! Ronaldo is played in by Cuadrado and gets one-on-one with Araujo in the area. After the Portuguese forward heads towards the byline, Araujo drags him down and the referee points to the penalty spot with no hesitation!
11' It has been a positive start by the Italian side so far. However, their only away victory at Camp Nou in the Champions League came back in April 2003 (2-1), having failed to win either of their two trips there in the competition since (D1 L1) - 0-0 in 2016-17 and 0-3 in 2017-18.
10' WIDE! Alex Sandro finds Ronaldo in the area and the Portuguese forward tees up Danilo 25 yards from goal. Unfortunately for Pirlo's side, the Brazillian's right-footed effort then whistles just wide of Ter Stegen's right-hand post.
9' Ronaldo ignores the option of Cuadrado out wide and instead steers a left-footed shot straight into the hands of Ter Stegen in the hosts' goal.
8' Ramsey and Alex Sandro exchange passes down the left before the wing-back does well to earn a throw-in for his side in the corner. The opportunity then fades away as De Ligt handles a loose pass on the edge of the area and Barcelona are awarded a free-kick.
6' This time it is De Jong's turn to escape a booking as he and Lenglet combine to foul Morata before the visitors can attack through the middle. That is two fouls in as many minutes which referee Stieler has let go.
5' McKennie smartly fouls near the centre circle to stop Pedri from breaking on the counter-attack, luckily for Juventus' midfielder, referee Stieler does not book him and instead opts to verbally warn him.
3' Griezmann dummies past Pedri's driven pass into the area but Trincao is not quick enough to pounce on the loose ball as Alex Sandro then clears long.
2' Alex Sandro looks to cut a pass back to the edge of the area, after good work from Morata, however, Pjanic is there to intercept before the visitors can test Barcelona's defence.
1' Referee Tobias Stieler blows his whistle to get this Champions League fixture underway!
The players are making their way onto Camp Nou's pitch and shortly kick-off will be upon us.
The hosts have gone unbeaten in their last four meetings with Juventus in the Champions League (W2 D2), winning two of the three games in this run that occurred in the group stage (D1).
Andrea Pirlo reverts back to a three-man defence in front of Buffon, who replaces Szczesny. Morata is back from suspension to partner Ronaldo, who renews his great rivalry with Messi here, as the pair meet for the first time since May 2018.
Ronald Koeman makes four changes from Barcelona’s 2-1 loss at Cadiz. Araujo comes in at the back, while Trincao and Pedri start on either wing. The other change sees Busquets drop to the bench for fit-again Pjanic.
SUBS: Dejan Kulusevski, Radu Dragusin, Rodrigo Bentancur, Cosimo Marco Da Graca, Gianluca Frabotta, Paulo Dybala, Wojciech Szczesny, Adrien Rabiot, Federico Chiesa, Manolo Portanova, Carlo Pinsoglio, Federico Bernardeschi.
JUVENTUS (3-5-2): Gianluigi Buffon; Matthijs de Ligt, Leanardo Bonucci, Danilo; Juan Cuadrado, Arthur, Weston McKennie, Aaron Ramsey, Alex Sandro; Cristiano Ronaldo, Alvaro Morata.
SUBS: Phillipe Coutinho, Riqui Puig, Samuel Umtiti, Junior Firpo, Neto, Sergio Busquets, Carles Alena, Matheus Fernandes, Oscar Mingueza, Inaki Pena, Martin Braithwaite, Konrad De la Fuente.
BARCELONA (4-2-3-1): Marc-Andre ter Stegen; Jordi Alba, Clement Lenglet, Sergino Dest, Ronald Araujo; Frenkie de Jong, Miralem Pjanic; Lionel Messi, Pedri, Trincao; Antoine Griezmann.
Both sides have already qualified from this group, with the hosts sitting three points clear of their visitors at the top. The hosts will remain top of the group so long as they do not lose by more than one goal here.
Hello and welcome to live coverage of the Champions League Group G fixture between Barcelona and Juventus.