JULIO Arca believes Sunderland will have to increase their concentration levels if they are not to endure a torrid return to the top flight.

The Black Cats were caught napping, to greater or lesser degrees, for all three of Charlton's goals on Saturday.

And with Liverpool at Anfield the next date on the calendar, the Argentine was frank in his assessment of the areas they need to address.

"We have to concentrate more because we are going to play against better teams than Charlton, with due respect to them," he said.

"You can't compare the two different leagues (Premiership and Championship).

"You are playing against perhaps the best players in the world in one of the best leagues in the world.

"We have to concentrate 110 per cent. We have come from a lower division and whereas last season we were flying and winning every game, this season we know we are going to have to work very hard to win games."

Sunderland's last sortie into the Premiership saw their ranks littered with experienced professionals, this time around Mick McCarthy has gone for lesser-known, but arguably hungrier, names.

"It's a really young squad," observed Arca.

"We have a few players with (Premiership) experience like Tommy Miller and Jon Stead. But there are others who are playing here for the first time so we have to learn with every game.

"The players who have never played at this level before, however, will maybe play at 110 per cent or more because they want to show everybody how good they are and that they can play in the Premier League.

"We are going to play against players that have played in World Cups and the Champions League, like at Liverpool next week, but I am sure our players will work very hard and will do everything they can to ensure we stay up this season."

Sunderland were given the run-around by Darren Bent on Saturday, the striker showing the Black Cats' fans just what they missed out on after boss Mick McCarthy failed in his attempt to bring the former Ipswich man to the Stadium of Light.

Sunderland and Charlton were in a tug of war for the England Under-21 international's services, but the Londoner's secured his signature with Bent hinting that the North-East side hadn't tried hard enough.

"I knew all about Sunderland but I am a Charlton Athletic player now," said the £2.5m man.

"It did cross my mind but as soon as I spoke to the manager and the chairman I knew Charlton was the right place for me.

"They made me feel like they wanted to sign me and wanted me to play for them.

"When the manager comes all the way up to see you it shows real loyalty and that's why I wanted to come to the club."

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