Barcelona 4-0 Man City: A Messi night for Pep's City
Barcelona 4 Man City 0
Not even Pep Guardiola can wake Manchester City from their recurring Barcelona nightmare - the one where Lionel Messi plays the uncontrollable bogeyman.
For the third time in three visits to the Nou Camp, City emerged beaten, reduced to 10 men and picked off by Messi, who treated his old boss to a hat-trick on his first return to Catalonia with his new club.
When Guardiola, Barca's glorious coach between 2008 and 2012, returned for the first time with Bayern Munich 18 months ago, he was on the wrong end of a 3-0 defeat, but it was worse this time.
Barcelona and Messi were good, make no mistake, but City were masters of their own downfall with each of Messi's goals coming as a result of the visitors' failings.
A Fernandinho slip led to the first, Messi was left unmarked for his second and only John Stones knows why he froze like a statue when Luis Suarez skipped around to tee up Messi for his third.
With goalkeeper Claudio Bravo sent off for deliberate hand-ball - Barca defender Jeremy Mathieu was later red-carded for a wild tackle on Raheem Sterling - City ended up with 10 men for the fourth time in five games against Barcelona.
And on a night when Guardiola chose to start without Sergio Aguero, everything that could go wrong did go wrong for City until Willy Caballero saved an 86th minute penalty from Neymar.
Guardiola has not been shy in making big decisions since beginning work at City this summer, as Joe Hart - shipped out on loan to Torino - will testify.
Omitting Yaya Toure from the club's Champions League squad was another surprise move, while the former Barcelona coach has also shown little desire to rush captain Vincent Kompany back into the team, despite the Belgian returning to full fitness.
Hart, Toure and Kompany had become a strong unit at the club, with only David Silva and Aguero coming close to matching their importance and standing within the dressing room, but there is now only one boss at the Etihad Stadium and that is quite clearly Guardiola.
No manager would choose to drop Aguero without being as powerful as Guardiola has already become, but that was the decision taken and he made no effort to palm it off as the Argentine being rested.
Guardiola insisted pre-match that Aguero's omission was tactical - "I want more midfielders" - and City's all-time leading Champions League scorer was benched in favour of a three-pronged front-line of Kevin De Bruyne, Nolito and Sterling, all of whom expected to flood midfield when Barca had the ball.
Was it bold? Was it risky? Probably both, but the tactic ensured that City were able to trade blows with Barcelona in a feisty first-half.
But when Luis Enrique's team were on top, City were stretched, with the likes of Fernandinho, Stones and Sterling all losing the ball carelessly in dangerous positions.
Messi's goal, his 13th in his last 13 games against English opposition, came following another example of a lack of focus on possession, when Aleksandar Kolarov was dispossessed by Javier Mascherano.
Mascherano then fed the ball to Messi, who scampered towards the City penalty area before attempting to pick out Andres Iniesta in the six-yard box.
Pablo Zabaleta beat Iniesta to the ball, which looked set to be cleared easily by Fernandinho until the Brazilian slipped.
Slipping was bad enough, but one can only imagine the horror Fernandinho felt when he raised his head to see Messi racing down on the loose ball.
It was an easy kill for the Barca forward, who dummied goalkeeper Claudio Bravo before sliding the ball into the net for his 87th Champions League goal.
City then claimed a penalty, rejected by Serbian referee Milorad Mazic, when substitute Lucas Digne appeared to handle a Sterling cross.
City already had a mountain to climb before Bravo turned it into Everest by giving referee Milorad Mazic no option but to dismiss him on 53 minutes.
Bravo's mistake gifted Suarez the ball 50 yards from goal and, when the forward took aim, the keeper handled. It was a clear red card and he was off.
Replacement keeper Caballero breathed a sigh of relief when Messi sent the subsequent free-kick over the bar, but the little forward was only delaying the pain for Bravo's understudy, as seven minutes later, he made it 2-0 with a low shot from 15 yards after being released by Iniesta.
Messi stroked the ball in from six yards on 69 minutes after Stones had been caught out of position.
He would have had four had he taken the penalty he won after being fouled by Kolarov, but Messi handed the ball to Neymar, only for the Brazilian to see his spot-kick saved.
Neymar, though, scored a fourth after slaloming through the City defence in the 90th minute.
BARCELONA: Ter Stegen, Umtiti, Mascherano, Pique (Mathieu 39), Alba (Digne 10), Busquets, Iniesta (Gomes 80), Rakitic, Messi, Suarez, Neymar. Goals: Messi 17, 61, 69 Neymar 89 Subs not used: Masip, Arda, Alcacer, Rafinha.
MAN CITY: Bravo, Zabaleta (Caballero 57), Otamendi, Stones, Kolarov, Fernandinho, Sterling, Gundogan (Aguero 79), Silva, Nolito (Clichy 58), De Bruyne. Subs not used: Fernando, Maffeo, Sane, Navas.
Man of match: Messi Match rating: 9/10
Referee: Milorad Mazic