Premier League - Stylish City beat Villa to top table
Mario Balotelli, who scored a hat-trick in this fixture last season, opened the scoring a dazzling overhead kick in the first half.
James Milner rounded things off with an excellent finish at the end of a move he initiated.
The result sends City two points clear of local rivals and reigning champions Manchester United, who were held to a 1-1 draw at Liverpool earlier in the day. It also ended Villa's unbeaten start to the league campaign under manager Alex McLeish, leaving them in mid-table.
Even with Sergio Aguero still recovering from a groin injury and David Silva, Edin Dzeko and Samir Nasri named only on the bench with Tuesday's crunch Champions League game against Villarreal in mind, City still assumed control with ease from the kick-off. Nigel de Jong also returned to the team for the first time in the league since August.
However Villa - themselves fielding an attacking line-up which featured Darren Bent, Gabriel Agbonlahor and Emile Heskey from the outset - almost caught City cold early on when Agbonlahor shrugged Joleon Lescott off the ball and surged for goal. His sidefooted effort was saved by Joe Hart and Stephen Warnock's follow-up glanced over the bar by the head of Vincent Kompany.
City eventually made their dominance count on the half-hour mark from a corner. The set piece rebounded off the chest of Micah Richards and sat up nicely for Balotelli to control and send a bicycle kick past Shay Given from the edge of the six-yard box. Of his nine Premier League goals, four have come against Villa.
The visitors may have seen a glimmer of hope in only being one goal down at the break, but that was soon extinguished two minutes after the restart. Warnock got in a terrible muddle trying to clear a long floated ball, leaving him on his backside and Johnson free to finish past Given for his second goal in as many games.
The game was ended as a contest five minutes later when Kompany rose highest at the near post to glance a header from a corner across the keeper and in at the far post.
Warnock made partial amends for his aberration that led to City's second goal by pulling one back on 65 minutes. Fabian Delph got his cross in from the right at the second attempt and Warnock made the most the space given him at the far post by taking a touch and firing past Hart.
Roberto Mancini responded by bringing on Silva (as well as Kolo Toure for the dazed Richards), but it was Milner who had the last word in this match. The England midfielder picked out Johnson with an inch-perfect curling crossfield pass and continued his run forward. Johnson jinks inside and laid the ball across the edge of the box, inviting Milner to bend the ball into the left corner.
Milner did not celebrate his goal of the season contender out of respect for his former club, but overall he and his team were merciless as they stepped over Villa on their way to the summit of the Premier League table.