Goals from David Silva and Nicolas Otamendi were enough to seal a 2-1 victory over rivals United, with Marcus Rashford briefly levelling for the hosts at Old Trafford.
With fellow Premier League titles hopefuls Chelsea also dropping points, it capped a perfect weekend for Pep Guardiola's charges.
The victory was also enough to set a new milestone in consecutive wins in the competition.
14 – Man City have won their last 14 league games in a row – the most by a team in a single English top-flight season. Momentum. pic.twitter.com/082h7oDeuI— OptaJoe (@OptaJoe) 10 December 2017
No other team has managed 14 straight triumphs in a single Premier League season, the mark reached by City on Sunday.
They share the overall record with Arsenal, although the Gunners managed their 14 wins over two campaigns.
14 - Man City's 14-game winning run is the joint-best in the English top-flight alongside Arsenal's run between February & August 2002. Superiority.— OptaJoe (@OptaJoe) 10 December 2017
The last time Pep saw his side drop points was on August 21 in a 1-1 draw at home to Everton.
And, since that point, they have been near-invincible, netting 45 times and conceding just eight.
City can go on to claim the record outright on Wednesday if they take a 15th consecutive win away to Swansea.