Barcelona 1 Atletico Madrid 1

Still nothing can separate these teams but in eight days’ time something must. Atletico Madrid and Barcelona met for the fourth time this season and for the fourth time they drew, after Neymar cancelled out Diego’s astonishing opener. Atletico again illustrated the qualities that have given them the best defensive record in the Champions League this season and they will go into the second leg with the advantage of that away goal.

It had appeared to be a disaster when Diego had first entered the fray. Not because it was he who came on but because of who had gone off - Diego Costa - hobbling slowly and sadly in the other direction, seeming to take much of Atletico’s hopes with him.

Costa lasted 30 minutes, turning Sergio Busquets brilliantly only to pull up with a hamstring injury. He was the second player to depart injured; Gerard Pique had suffered a heavy fall in leaping for a header a quarter of an hour in.

Costa’s departure was a severe blow. He has seven goals in five Champions League games. Atletico were already without the suspended Raul Garcia. David Villa was still there, though, and the best opportunities of the first half came his way.

The first arrived after just four minutes when he swung a shot wide after Arda Turan had taken advantage of Jose Pinto’s poor clearance to find him; the second came just before the interval when Pinto stretched to push away Villa’s curling shot towards the far post.

Between those chances there was a familiar, if broken, pattern to this game. Atletico’s early start, pushing Barcelona back, had faded. The ball was largely Barcelona’s but there remained a vulnerability about them at the back and creating openings was proving difficult.

In the opening 45 minutes Neymar shot over but Andres Iniesta had the best opportunity. Lionel Messi escaped Miranda with a wonderful piece of footwork and delivered a sharp pass into Iniesta to hit hard and low. As Thibaut Courtois dived, so did Diego Godin, flying across to make a superb block.

Diego Simeone had said that Barcelona’s game is built around the ball while Atletico’s is built around the space and that was a fairly accurate reflection of how the match was progressing. Barcelona’s passing lacked the swift precision needed to open up spaces, 11 yellow shirts invariably between them and the goal. Cesc Fabregas was unable to influence the game, Messi too, and the longer it went on the more surprising the absence of Pedro or Alexis was. When Atletico headed forward they found space opening before them. The danger was clear.

What no one could have imagined was that it would come the way it did. Diego received the ball from a short free-kick five or six yards outside the top right-hand corner of the penalty area, after a foul from Iniesta. He turned and stepped away from Xavi then thumped a swerving rocket shot into the top corner of the net, inside Pinto's near post. It was a stunning shot and the Brazilian Diego sank slowly to his knees, looking to the skies. Guardian Service