WOLVERHAMPTON, England - Manchester City boss Roberto Mancini has warned Adam Johnson to knuckle down if he wants to avoid wasting a glittering talent that could make him one of the best wingers in Europe.

Johnson turned in a sparkling individual performance with two assists and a goal in the 5-2 romp at Wolves on Wednesday which earned City's place in the League Cup quarterfinals.

But rather than heaping praise on the England international, Mancini took the opportunity to give Johnson another warning about the dangers of taking his talent for granted.

Mancini could have been content at watching Johnson orchestrate another victory to follow swiftly on the heels of the 6-1 victory against Manchester United at the weekend.

But while happy with Johnson's display, Mancini is always left wanting more.

It is the second time in 12 months that Mancini has felt the urge to challenge Johnson and he said: "He is the only winger we have got. If he wants to improve he will have a lot more chances to play. You can improve when you are 30 or 31.

"Adam is young; it is only his third season. I am disappointed when he does not put everything on the pitch.

"Sometimes he thinks it is enough to score a goal and make an assist. He thinks that is OK. He can improve and want to score a goal and another assist in his next game.

"He played well and I think he can be one of the top wingers in England and Europe. That is my opinion, but there are areas of his game he can improve. He can run back more to help the team and he can be more consistent."

City could meet United in the last eight for a chance of a repeat of the derby victory and Johnson, who did not even make the squad on Sunday, admits his side would fancy its chance against anyone at the moment.

"We have not thought about meeting United, but we will play anyone at the moment because our confidence is up," he said.

"We are a confident team at the moment and we are playing well. Whoever we have to play against we are happy to go home or away against them.

"It does not matter where we go. We can beat anyone when we are in this mood."

City has smashed 45 goals in its past 15 games and is the new rampaging force in the English game.

Edin Dzeko added to his two goals in the 6-1 romp at Old Trafford with another double as Mick McCarthy's men were put to the sword, with Samir Nasri and a Dorus De Vries own goal completing the rout.

Mancini rested all 11 of the stars who started at Old Trafford and his 120 million reserves were still far superior to a Wolves side who suffered more misery just days after McCarthy was abused by home fans during a 2-2 draw against Swansea.

McCarthy feels Mancini's claim City can win all four trophies this season is much too tall an order and asked whether it could be stopped, he said: "Yes, one of the better teams can stop them."

Agence France-Presse