Aguero scored his goals in the second half, propelling City to a 16-point lead at the top of the standings.
Mahrez only returned to training on Friday after a self-imposed 10-day absence following the blocking by Leicester of a move to Manchester City, during which he missed games against Everton and Swansea.
Although one of the best defensive outlets in the league, United are still short in the midfield and at the back.
Man City have agreed a deal in principle to sign Shakhtar Donetsk's 24-year-old Brazil midfielder Fred for £44.5m this summer...
Even Mendy doesn't understand how De Bruyne does it. The attack of the team shows a very high level of football, the players score in nearly every match, so it's no surprise that in 26 rounds Manchester City disappointed the opponents 74 times, the defense also feels confident and missed only 19 goals.
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She said that she tried to stop the president tweeting , without success. "She has no contact now", Shah added. ROSS MATTHEWS: Don't say that because we are anxious but I need you to say 'No, it's going to be okay'.
Leicester made a double substitution with Mahrez and Iheanacho coming on to try and salvage the game. The England winger contrived to miss from three yards as City dropped two points at Burnley but this time made no mistake from a similar distance after just three minutes. Sterling gets the hosts off to a flyer!
Leicester City needs to work out their situation with Mahrez.
But Pep Guardiola's runaway league leaders failed to build on their blistering start, with Sergio Aguero just unable to reach another De Bruyne ball in soon afterwards. 3-1, min. 53, Aguero. Aguero at the double!
77' - GOAL! Man City 4-1 Leicester City. "One of the best players we have, no doubt about that, is the guy who runs the most and fights the most". It was the first time in my life, it was an exception.
Mahrez, who was voted Professional Footballers' Association player of the year in 2016 when Leicester won the league, has scored eight goals this season and has seven assists.
"I have been a part of the Leicester City team that has achieved much success including promotion to the Premier League and being champions of the League".