Manchester City's lead at the top of the Premier League is back to three points courtesy of Edin Dzeko's first goal in two months and a measured performance against willing but limited opponents. Roberto Mancini's team may have to be significantly improved when they host third-placed Tottenham Hotspur on Sunday but they can reflect on a satisfying evening's work and it is a pity that once again there was the sideshow of their manager waving an imaginary card.

Mancini was entitled to feel that the referee, Martin Atkinson, should have ruled that Maynor Figueroa's handball had denied Sergio Agüero a clear run at goal and was a red-card offence. By now, however, he should also appreciate that English football regards what he did next as distasteful. This was the second time in four games he has done it and, whatever the rights and wrongs about the refereeing, it is a habit he should lose, bearing in mind he issued an apology after the first one. If nothing else, it distracts from what his players are doing on the pitch.

This was not a night when City fully exposed the gulf between themselves and the team at the bottom of the table butthey were still comfortably the better side and it would have been a rout had Dzeko and Agüero been more clinical in the second half. Mancini was shaking his head at the final whistle and the post-match conference was slightly tense. He was unhappy, he said, because of "everything" but would not elaborate. What can be said with certainty is that Atkinson's refereeing was prominent in his thoughts.

His team were not at their fluent best but Wigan, with only 18 goals in 21 league fixtures and one home win all season, were generous opponents. Dzeko's goal arrived in the 22nd minute and, after that, there were so few moments when the team in 20th place threatened to equalise it felt incongruous that Gary Neville, in the television studio, nominated Joe Hart for the man-of-the-match award.

Neville's reasoning was based on the way Hart saved his team when James McCarthy found space inside the penalty area, on a rare second-half breakaway, and the goalkeeper was required to make his one meaningful save of the night. Otherwise City were seldom troubled and there was rarely the sense they were missing their captain, Vincent Kompany, through suspension. Stefan Savic had looked vulnerable against Liverpool in last week's Carling Cup game but this was a far less demanding examination. Hart, collecting his champagne, made a point of mentioning Joleon Lescott.

Between them Agüero and Dzeko missed enough second-half chances to take City to last season's tally of 60 league goals with four months to spare. Instead they remain three short but Dzeko's 14th of the season should soothe his confidence after a difficult spell since his last strike, on 2 November.

The Bosnian's form can fluctuate from brilliant to abject and he will wince when he sees the replays of his weak finish, taking the ball off Agüero's toe after the Argentinian had waltzed past three challenges and was threatening to score one of the goals of the season. Even so, Mancini will be relieved Dzeko is scoring again when Mario Balotelli's ankle injury and Carlos Tevez's disappearing act have left Agüero as their only other forward.

Wigan had begun the game playing with a confidence that would not normally be associated with a team at the bottom of the league but it was such a straightforward goal it is clear to see why they are struggling.

It originated from a free-kick on the left. Samir Nasri was the decoy, standing close to the ball before David Silva curled it into the penalty area. Dzeko, the tallest man on the pitch, eluded his nearest opponent, James McArthur, and the striker's header was expertly glanced beyond Ali al-Habsi.

The temptation from this point was to believe it would be a story of almost unremitting City attacking but it was not until the start of the second half they reminded us why Mancini took exception recently to Sir Alex Ferguson's observation that Tottenham Hotspur were the most attacking side in the league. Habsi saved brilliantly from Dzeko and Silva in quick succession. Dzeko's shot trickled into the goalkeeper's arms after Agüero's run.

Suddenly it felt like a top-versus-bottom game, with Silva, Agüero and Dzeko interchanging positions, elusive opponents as Wigan were pressed into their own half. Agüero turned two more chances wide of the goal and, at this point, it was a backs-to-the-wall operation for the home side.

The problem for Wigan was that when they had possession they were so sterile in attack. They moved the ball well at times but their poor goal return so far this season is no fluke. Their top scorer in the league is a midfielder, Jordi Gómez, with four goals.

Figueroa's handball came with only two minutes of normal time to go and, though Mancini had a legitimate grievance, the tension that was evident on the touchline seemed far more extreme than on the pitch.