IT WAS not scoring goals that was the problem this time — it was stopping them.

Edin Dzeko’s brace, one from Sergio Aguero and a harsh own-goal by Norwich keeper Mark Bunn earned Roberto Mancini’s Manchester City a deserved win.

But they were made to sweat after some dodgy defending and a stupid head-butt from Samir Nasri saw the midfielder sent off at Carrow Road.

After City’s shock 1-0 defeat at Sunderland on Boxing Day, the last thing they needed smack-bang in the middle of the festive fixture list was a tricky trip to Norwich.

The Canaries had already seen off Manchester United and Arsenal at Carrow Road and clearly fancied another big scalp here.

And they had reason to be optimistic too, given Mancini’s side’s recent poor form which has seen rivals United open up a seven-point lead at the top of the table.

Part of City’s problem this season has been the inability of their strikers to rediscover the devastating form that helped them net their first Premier League title in May.

Of their four multi-million pound attackers, Aguero, Dzeko and Mario Balotelli are all down on their like-for-like record.

In fact, only Carlos Tevez has a better record than this time last season — and that is because he was on strike back then.

But finding the net was not the problem yesterday as preferred supersub Dzeko made the most of his first start since the 1-0 Champions League defeat to Borussia Dortmund on December 4.

If the 26-year-old was looking to make an impact, then he wasted little time in proving it to his manager.

It took the Bosnian just 81 seconds to open the scoring when he completed a neat move that had torn Norwich wide open.

Dzeko started it by heading into the path of Aguero, who burst down the right and crossed to David Silva.

The Spaniard showed great control and vision to pick out the unmarked Dzeko, who calmly slotted the ball past Bunn. If Norwich were not rattled then, they certainly were two minutes later when Dzeko doubled the lead.

This time, Vincent Kompany got the better of Bradley Johnson in midfield to tee up Argentine Aguero.

He then crossed for Dzeko, who was allowed too much space by the Canaries defenders and, again, he applied a cool finish.

City’s brilliant start and Norwich’s recent defeats to West Brom and Chelsea had the Carrow Road faithful fearing the worst.

But to their credit, Norwich showed their resolve when Anthony Pilkington pulled a goal back after quarter of an hour.

The midfielder slotted home a free-kick after Kompany fouled Robert Snodgrass on the edge of the box.

It was a good strike from Pilkington but questions will be asked as to whether Joe Hart should have done better after allowing the shot to wriggle under his body.

City’s two-goal cushion was almost restored in bizarre fashion when former defender Javier Garrido almost chipped the ball past Bunn and into his own net when trying to make a clearance.

Kompany was denied when his bullet header from a corner was cleared off the line, while Yaya Toure fired wide from Nasri’s pass.

It proved to be the ex-Arsenal man’s final contribution as he was dismissed for squaring up to ex-Spurs defender Bassong a minute before half-time.

In fairness, Bassong did launch into Nasri with a crunching tackle that left him in a heap on the floor. However, it was Nasri’s stupid reaction when he went head-to-head with Bassong which drew the red car from referee Mike Jones’ pocket.

And much to Mancini’s dismay, Bassong only received a caution when he was just as guilty as Nasri.

City’s smiles were restored on 50 minutes when Aguero added a third with a low drive past Bunn after latching on to Toure’s diagonal pass.

But their joy was short-lived as Norwich pulled it back to 3-2 through Russell Martin as City failed to clear.

Snodgrass picked out Bassong and he headed back across goal where Martin was able to divert the ball past stranded keeper Hart.

Dzeko was instrumental in City’s fourth on 67 minutes.

He got the benefit from an offside decision before powering his shot at Bunn.

The keeper saved his first effort and palmed the ball on to the post — but it rebounded and hit him on the back before rolling in.

There was still time for another twist when Hart and his defence blundered again as Martin proved an unlikely scorer for a second time.

Hart flapped at a corner before Harry Kane’s shot was blocked.

The ball fell for Bradley Johnson and his shot was deflected in by Martin.

Late on, Aguero was denied brilliantly by Bunn while Norwich pressed for an injury-time equaliser.