Kevin De Bruyne and Kelechi Iheanacho fired the visitors into a two-goal lead before Zlatan Ibrahimovic pulled on back before the break as City claimed a thoroughly deserved victory.
The battle of wits between Guardiola and Jose Mourinho, who were facing off for the first time in the Premier League, dominated the pre-match discussion and the Catalan’s men proved superior for long spells.
De Bruyne raced onto Iheanacho’s flick on to open the scoring with a composed finish and 11 minutes later the Nigerian was in the right place to tap home a rebound after City’s No.17 saw an effort bounce back off the post.
United were handed a lifeline when Ibrahimovic converted a half-volley after Claudio Bravo spilled a free-kick but City held firm to claim all three points.
Watch the best of the action in the video above.