United had to at least draw to keep the title race mathematically alive but they were stunned at Old Trafford when Jay Rodriguez headed home after the break.
The Premier League points and goals records are also likely to be smashed but the true test of whether City deserve their status in the list of all-time greats will be what comes next. I was unfortunate enough to play against that quality United side that dominated in the '90s, but this side would have beaten them - that's how good they are.
However, the Gunners now risk the ignominy of finishing the season seventh behind Burnley after a fifth consecutive away league defeat as they lost 2-1 at Newcastle on Sunday.
Club captain Vincent Kompany watched the game at a family members' house, and he was clearly ecstatic after winning his third Premier League title.
Mourinho and United still have a chance of winning a trophy this season - the FA Cup - and on Saturday face Spurs at Wembley stadium in the semifinals of the tournament.
"This one differs in that we were consistent the whole season and we were able to play at the level we're expected to perform at".More news: 7 inmates dead and 17 injured after SC prison fight
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Today I am happy and I suppose my team-mates might roll their eyes at this, but I want to see the reaction now.
"I've seen many teams win it where they've been champions all season and it's a first for me".
"But that will be year by year, so perhaps they will convince him to stay one more year and then in a year's time do exactly the same".
But they were back to their irresistible best against Spurs as Gabriel Jesus and Ilkay Gundogan put them 2-0 up early on, with Sterling sealing the win after Christian Eriksen had given the hosts hope. "Those two teams barely had a weakness between them".
"He unlocks everything but when you think about it he did much, much better than last season and that was important".
Central midfield is the most pressing concern, with Fernandinho needing a back-up or a foil in his important role as the anchorman behind playmakers Kevin De Bruyne and David Silva. Only Sir Alex Ferguson and Jose Mourinho have managed to do that so far and in recent years follow ups have proved very hard.
Pep Guardiola might have only one year left as he nears the end of the second year of his three-year deal.