Their second goal came in the last minute when Dani Alves collected a pass from substitute Neymar and fired through goalkeeper Joe Hart’s legs to give City an almost impossible task of rescuing the tie in the second leg on March 12.

The defeat sparked an out-of-character attack from Pellegrini who accused Swedish referee Jonas Eriksson of favouring Barca and the Chilean risks a reprimand and possible severe punishment from soccer’s European governing body Uefa.

“I spoke to him at the end and told him he should be very happy because he decided the match,” Pellegrini told reporters.

“Barcelona had no chance to score until the penalty against Demichelis.

“The referee was not impartial. He did not have any control of the game. I think it was not a good idea to have a referee from Sweden in such an important match.

Asked why it was relevant that the referee was Swedish, he replied: “More important football is played in Europe than in Sweden so a big game with two important teams – that kind of game needs a referee with more experience.”

Eriksson, a Fifa referee since 2002 who is on the list for this year’s World Cup finals in Brazil, has refereed 86 Uefa matches and this was his 22nd Champions League game.

It was also City’s first in the knockout rounds of the competition and they rarely showed the kind of form that has brought them 117 goals in all matches this season and prompted talk of a quadruple haul of trophies before this setback.

Barca, with a three-pronged attack of Messi, Andres Iniesta and Alexis Sanchez in front of a typically fluid three-man midfield, dominated the first 20 minutes, allowed City back in the game briefly, then took control again after the dismissal.

Their coach Gerardo Martino said he was delighted with the win but was not taking anything for granted for the return.

“I am not so confident yet for the second leg. Our intention was to win and I think it’s a fair result.

“But when we allowed City to have the advantage for 10 minutes in the first half and 10 in the second they made it risky for us.

“We have had a good away win and now we have to repeat the performance at home. But City lost at home to Bayern Munich in the group stage and then won away. They are a very dangerous opponent.”

City had few chances, with the best falling to David Silva in the 77th minute when he chested the ball down and then volleyed at Victor Valdes who saved well.

But on the whole Barcelona silenced the home fans and blunted City’s attacks which were few and far between.

The two sides, who had scored 228 times between them this season heading into the game, failed to produce the goalfest that many expected.

However, the estimated global audience of 250 million would have enjoyed seeing Barca reproducing their trademark passing game and winning after a relatively tricky season by their own exalted standards.

“People have been saying this is not the same Barcelona of previous years but we’ve got a great a result tonight and we’ve proved a point to some people,” Barca midfielder Cesc Fabregas said.

“We are not there yet, though. They are a good team and we still have to work hard to get through.”

The balance tipped Barca’s way with Demichelis’s dismissal, which will keep him out of the second leg at the Nou Camp.

The defender appeared to have fouled Messi outside the area but Eriksson had no doubt, pointing to the spot, and showed Demichelis a red card, allowing Messi to stroke the ball past Hart to put the visitors ahead.

“Two-nil is very tough on us. When it was 11 versus 11 we were in the game but with a man less and with their individual quality which is so high it was very hard,” Manchester City captain Vincent Kompany told ITV.

“If they play as they can in the second leg it will be very hard but we still have a chance.”