Barca know the pace of Ousmane Dembele is one of their most potent weapons. The Frenchman is being watched by a group of Rayo players and, after slipping away from one, is hauled down by another on the edge of the box.

The home fans scream for a penalty... the referee is not interested. Dembele is furious.

Busquets is hacked down inside the Rayo half. Chance from the dead ball. The ball is clipped in but Frenkie de Jong can't get a full head on it.

The danger isn't quite over, though. Rayo keeper Dimitrievski is alert to alleviate the danger but only gets the ball away as far as a Barca shirt. The ball comes wide to Dembele on the right but he isn't able to pick out Alba at the far post.

Ooof! Rayo get away with one. Defender Catena casually tries to play out from the back - too casually - and almost gets caught in possession by Pierre-Emerick Aubameyang.

Back to the full complement. On we go.

Barcelona have the bit between their teeth now, ramping up the pressure.

Ousmane Dembele tries a rabona to cross into the box... that doesn't go down well with the home fans.

The ball remains loose and Jordi Alba - Barca's biggest attacking threat so far - fires over.

A short stoppage as one of the Rayo players needs some treatment.

Barcelona's Gavi skips into the Rayo box, taking down a high ball and then going over a defender's leg.

Penalty? Barca think so. But the referee doesn't and his opinion is the one which matters.

Xavi also strongly disagrees, earning a yellow card for giving some grief to the fourth official.

Better from Barca. Sergio Busquets finds himself deep inside the Rayo half, picking out the run of fellow old-stager Jordi Alba. He bends the ball just over the bar, while a few moments later another Barca attack ends with away keeper Dimitrievski using his feet to clear.

Rayo are enjoying the scrap, winning the ball back from Barca regularly. Keeping it is the problem though. They lose possession to Busquets, who pings a quick ball forward to Dembele.

The Frenchman looks to have the run on his marker, but a heavy touch from the long pass sees the chance disappear.

Barcelona are struggling to make any in-roads inside the Rayo half and that's because the away team's press is proving difficult to bypass at the moment.

Talking of pace, Ousmane Dembele is no slouch either. The Barca forward goes off on a run down the right, but Rayo left-back Fran García quickly slides in to stop the Frenchman.

Rayo have already had success with an angled pass into the Barca box and look to use that tactic again.

Alvaro Garcia, the man who scored the opener, has serious wheels and looks to use his speed again to get in behind.

This time the Barca defence are slightly more alert.

Barca are dominating possession, as you would expect. They've had about 70% of the ball but are not yet finding a way to feed Pierre-Emerick Aubameyang.

Ronald Araujo looks to carry the ball out from the Barca defence and pierces the Rayo lines with a ball into Gavi.

Gavi has been instructed to get the ball out wide quickly by the animated Xavi, but the teenager can't find Frenkie de Jong or Sergio Dest.

A few whistles from the home fans as their frustration gets the better of them.

Time for the Barca onslaught? The home side pack the Rayo box and the ball pings around the penalty spot. Eventually it falls for Ronald Araujo - probably not the player the home fans wanted it to fall to - and he swivels to fire a tame effort low at the keeper.

Jordi Alba might be heading into his mid-30s, but he can still fly down that left flank. The Barca full-back races forward on the overlap, collecting the pass and firing in a fizzing cross. Luckily for Rayo, Oscar Valentin is well-placed to head out for a corner.

Plenty of time though for Barca to find their rhythm and get back into this game. Ousmane Dembele tries to make something happen down the right, but the ball into the box doesn't find a team-mate.

There is a stunned silence inside the Nou Camp. Perhaps the fans there wish they had gone to the seafront tonight instead.