Manchester City's attacking instincts can leave them exposed at the back and goalkeeper Joe Hart wants the side to tighten up defensively after going eight games without a clean sheet.

City began the season rock solid at the back, going five straight Premier League games without conceding.

Some of the sudden slackness can be put down to the absence of injured captain and central defender Vincent Kompany, who came off the bench in stoppage time in Wednesday's 2-1 win over Sevilla in the Champions League.

All five of their clean sheets came with Kompany in the side. The Belgian has been sidelined since mid-September with a calf problem.

"We are working hard as a team" said Hart.

"We appreciate we are quite an attacking team so we can leave ourselves a little short at the back sometimes and it's something we want to improve, but we want to improve all over the pitch to be the team we want to be."

While goalkeeper Hart is understandably focused on City becoming harder to score against, Kevin De Bruyne, who grabbed the winner in stoppage time against Sevilla, said it was their commitment to attack that earned the points on Wednesday.

"Even though we didn't have our best game, in the end we tried everything to look for the victory and thankfully in the end we could score," De Bruyne said.

"To get a draw (in Spain) isn't that bad but I think we have a team to attack. Sevilla are very good in possession but we will try to get the three points there too," he added.

Manager Manuel Pellegrini heaped praise on De Bruyne, calling him the "perfect player" for the club after the 24-year-old midfielder scored his fifth goal in nine appearances.

"We bought Kevin because we knew is a very creative player who can score and create goals and in that respect he was the perfect player to bring to our club," Pellegrini said.

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