Algerian Yacine Brahimi scored the only goal of the game after 16 minutes as Barca failed to find a way past the inspired Orestis Karnezis in the Granada goal.

Just three days after being dumped out of the Champions League by Atletico Madrid, Barca trail Atletico by a point having played a game more and could end the night in third place should Real Madrid beat Almeria at the Santiago Bernabeu.

"It is a step backwards. It was just one move, for their goal, which we were punished for despite all the effort we put in," Barca midfielder Andres Iniesta told Canal Plus.

And the Spanish international was at a loss to explain how his side had passed up so many chances despite racking up 29 efforts on goal and enjoying over 80 percent of the possession.

"At times it is difficult to explain when you lose. We lacked goals, but the rest we had under control.

"They only had the one chance with their goal. Teams like this, that are playing for their lives, live off just getting one chance. It is undeserved, we ought to have won but we haven't done so.

"We did everything to score. All we lacked was the finish, which is the most difficult part and makes the difference."

Barca boss Gerardo Martino shared Iniesta's analysis of the game and said he couldn't fault his players' performance apart from when it came to putting the ball in the net.

"We no longer have matters in our own hands, but I couldn't ask for anything more from the players," he said.

"They tried in every way possible. They created plenty of chances, but today it wasn't to be. I can't criticse them for anything apart from obviously not finishing off the chances we had."

Martino had made four changes from the side that started Wednesday's 1-0 defeat to Atletico with a makeshift back four made up of reserve full-backs Adriano and Martin Montoya alongside natural holding midfielders Javier Mascherano and Sergio Busquets.

It was Montoya who had Barca's first opening as he headed straight at Karnezis 12 minutes in.

However, just four minutes later Granada took advantage of Barcelona's unsettled defence to open the scoring as Brahimi sped past Busquets and forced the ball past Jose Manuel Pinto at his near post.

Neymar then headed over from a fine Montoya cross before the Brazilian forced Karnezis into his first serious save of the day with a curling effort from outside the area that was beaten away by the Greek 'keeper.

It was one-way traffic in the second half as Barca were denied on numerous occasions by Karnezis.

Cesc Fabregas was the first to come close as his low volley was turned behind before Neymar came within inches of an equaliser with a low drive that flew across goal and just past the far post.

Karnezis then made two great saves in as many minutes as he got a hand to Lionel Messi's inch-perfect free-kick to prevent the ball finding the top corner and then held Busquets' effort as the Spanish international bundled the ball goalwards from the resulting corner.

Even when Karnezis was finally beaten, on-loan Liverpool defender Tiago Ilori was on hand to clear another effort from Neymar off the line as the ball trickled towards goal.

Iniesta then saw another two efforts fly just past as Barca threw everyone forward and they were nearly caught on the break when Youssef El-Arabi fired straight at Pinto with just the 'keeper to beat two minutes from time.

Karnezis was forced into one final save by a Pedro Rodriguez volley in stoppage time which he held with consumate ease to dent Barca's title challenge and take Granada six points clear of the relegation zone.