Barcelona v Manchester City: Javier Mascherano forced to defend Barca against angry fans

Barcelona's bid for the La Liga title has taken a hit in recent weeks

Javier Mascherano defended his manager’s record (AP)

Tomorrow night he faces the challenge of marking Sergio Aguero, but Javier Mascherano was today defending Barcelona against a threat far closer to home – the club's own critical supporters.

"Wait for us to be dying before you kill us off," the former Liverpool midfielder said of the wave of criticism and negativity engulfing Barcelona as they prepare for the last-16 second leg against Manchester City.

Barça were six points ahead of Real Madrid in the table last year but a dismal 2014 has led to Real turning the tables, establishing a four-point lead at the top of La Liga. It's a 10-point swing that has the club's opinion-formers already planning a future without coach Gerardo Martino at the end of the season.

After their worst performance of the season at the weekend against Valladolid, criticism has intensified but Mascherano said: "We just have to keep doing what we have been doing for so many years.

"Our heads are not down. We don't analyse things as the media do. We are in the final of the Spanish Cup and have an advantage in this game and winning the league is still possible."

He was asked about stories circulating after the weekend defeat that the team are not training as well as they were two seasons ago under Pep Guardiola. Mascherano laughed at the suggestion.

"If there is one thing we have, it is unity," he said, before giving a stirring defence of his under-fire coach Martino. "Maybe he does not have a big name but he is 15 years in this job [as a coach] and no one has given him anything; he has had to fight to get to where he is.

"He had to go outside of his home country to get recognition," he said referring to the coach's first success in Paraguay. "He then went back home, won things in Argentina and then he went to the World Cup and almost knocked out the winners [Spain].

"Then he beat Brazil in the South American championship. When you start disrespecting someone, you should take a look at their CV. He will have gone through much worse things than two defeats in 15 days.

"People want to make us believe it's over but we know it isn't. We can still fight for all three trophies. We have already won one trophy – the Spanish Super Cup – and are in three other competitions."

There was also plenty of emphasis on the game being in the Champions League, where Barcelona have dominated winning it three times since 2006, and not in the league which increasingly looks Madrid's to lose.

What Barcelona supporters have most criticised the team for is the lack of competitive edge and hunger, with it being pointed out that in the team that lost 1-0 to lowly Valladolid at the weekend, the players on the pitch had won 147 trophies between them.

There is a perceived motivation deficit after so much success but Mascherano said: "We know football has no memory. We know we cannot hang on to what has happened in the past.

"When you are in pre-season, you dream about being in exactly the position we are in now – it's March and we are still in three competitions." There was even a pop at the nostalgia for Guardiola that clouds all that happens at the club. "In my second year here we only won the Copa del Rey," he said.

And there was a tired rub of the face when the Argentine was asked about his compatriot Leo Messi, who also had the finger of blame pointed at him for not showing sufficient leadership qualities at the weekend. "He is our talisman," he said of the striker who is now five goals from Raul's all-time Champions League scoring record of 71.

The other Argentine striker on the pitch tomorrow could end up having an even bigger say in events. Aguero returns after missing the first leg and Mascherano said: "He is one of the best five strikers in the world and if you let him, then he will ruin your night. We have to make sure he has a very uncomfortable night and he does not feel in his natural habitat."

Martino defended accusations that his star-studded forward line was misfiring. "They have not played together a great deal but when they have they have linked up well," he said of Messi and Neymar.

The Brazilian was accused of strolling through the defeat at the weekend and being guilty of missing the only real chance that Barcelona created. Having just come back from scoring a hat-trick for Brazil against South Africa, this only increased the suspicion that some players have their sights set on the World Cup and are letting the distraction affect their form.

Martino said despite the negativity surrounding Barcelona's season, the supporters inside the stadium will not let the side down.

Barcelona have a 2-0 lead to protect and Martino said: "If you are playing at home and the opposition score, that always makes for an uncomfortable atmosphere but I'm sure the fans will understand they have a role to play."