Manchester City 1-0 Everton

Manchester City have won four straight league games for the first time since the end of last season

• Man City move three points behind Chelsea

• Sergio Aguero suffers knee ligament damage

• Everton have won once in six league games

• Toffees stay 11th in the table

Manchester City moved to within three points of Premier League leaders Chelsea after a hard-earned win over Everton at the Etihad Stadium.

Yaya Toure's penalty, after Phil Jagielka was controversially adjudged to have fouled James Milner, secured a fourth straight league win.

But the victory came at a cost as key striker Sergio Aguero made a tearful early exit with a knee injury.

Everton had their chances, with Romelu Lukaku denied brilliantly by Joe Hart.

City's fourth straight league win leaves Manuel Pellegrini's men breathing down Chelsea's neck five weeks after finding themselves 11 points behind the Premier League leaders.

But victory came at a cost.

They will already be without suspended midfielder Toure for Wednesday's crucial Champions League tie at Roma, while captain Vincent Kompany is struggling with a hamstring injury and David Silva is recovering from a knee problem.

Now Aguero may be missing after the Premier League's top scorer limped off against Everton.

The mood of the City fans inside the Etihad had been boisterous after Newcastle had earlier ended Chelsea's unbeaten start to the campaign but that changed when the Argentine striker was left clutching his knee.

Aguero had managed to get to his feet following a Seamus Coleman tackle but, moments later, his knee appeared to jar as he stretched for the ball while under pressure from Muhamed Besic.

The 26-year-old was in tears on the sidelines as he was replaced by 18-year-old midfielder Jose Pozo, who has yet to start a senior game for City.

The exit of their talisman threatened to derail the reigning champions.

In a tetchy game of six bookings, defender Eliaquim Mangala was fortunate to escape with just a yellow card on his return from suspension after an ugly high kick on Samuel Eto'o left Everton's Cameroon forward writhing in agony.

But moments later, City went ahead in controversial circumstances.

There looked little danger when Toure's pass found Milner in the Everton area. But referee Andre Marriner left Everton incensed as he pointed to the spot after the City midfielder went down in the area under Jagielka's challenge.

With Aguero off the pitch, it was left to Toure to convert the penalty.

That put City ahead but they were far from their fluent best against an Everton side who have won once in six league games and amassed 10 points fewer than after 15 matches last season.

It might have been different had Hart not produced a brilliant one-handed stop to deny Lukaku after the Belgian found himself behind the City defence.

Kevin Mirallas also had a goal-bound half-volley deflected behind, but City could have won by a more handsome margin.

Tim Howard used a shin to deny Pozo his first Premier League goal before the teenage substitute was replaced himself by Edin Dzeko.

Manchester City manager Manuel Pellegrini: "It is important to know how to win just 1-0 in some moments.

"December is a very difficult month where we have to play seven Premier League games.

"It's not a month where you win the title but it's a key month to try and we want to start the next year leading or at least trying to be near the top."

Everton manager Roberto Martinez: "It's not a penalty in a million years. Jagielka cannot disappear. It's a natural action to get to the ball.

"Football is a contact sport, if you look at the reaction of James he's trying to get up and fight for the ball.

"But putting aside the referee's performance, our first-half performance on the ball was not as good as it could be."

Sergio Aguero had scored 14 goals in his previous 14 Premier League appearances

Yaya Toure has scored all seven of his penalties in the Premier League

It is the first time Everton have failed to score in an away Premier League game since April

Roberto Martinez has faced Manchester City 11 times in the Premier League as a manager, and never been on the winning side

This was Manchester City's second clean sheet in their last 17 Premier League encounters with Everton