However, they put up a woeful performance at home to the Premier League's "basement boys" and Jay Rodriguez's 73rd minute strike condemned them to a shock 1-0 defeat that gifted City the title.
Meanwhile, Vincent Kompany barely let City's title celebrations begin before setting his side the challenge of making it two in a row next season. "So happy to be able to share another trophy with our unbelievable fans", the 32-year-old Belgian defender said on Twitter.
They could yet beat three significant Premier League landmarks set by Chelsea - the highest points tally of 95 in 2004-2005, the most wins in a season at 30 in 2016-2017 and the most goals scored at 103 in 2009-2010.
"I won eight titles and I am not (over) the moon because I won against Manchester City", he added. They lost only two matches, that is why they were champions. "This is not a dynasty, it is one title we've won".
Scroll down for some of the best reaction to City becoming champions.
"I saw lots of people in the moon because we won against Manchester City". You could see the difference in the attitude to players compared to last week. The Gunners did draw 12 games that season, and won nothing else, but in avoiding a single defeat they completed a remarkable campaign that deserves recognition alongside the very best.
That delay, however, lasted only one week after Manchester United (22-5-6) were indifferent offensively in a stunning 1-0 defeat at Old Trafford to the Baggies that marked just their second defeat at home to a last-place team in the Premier League era. We're delighted that we got the goal that way.
The irony that this is exactly how Manchester City play will not be lost on anyone.
"We were masters in complication, everything was complicated".
"I hope that we can have a happier Monday in seven days".
"As much as this has been a record breaking season, this one's for you, the fans, this is why we do it!" said the skipper.
Guardiola said he wouldn't be watching United's game at Old Trafford on Sunday, but instead would be enjoying a round of golf with his son.
As for the future of the manager, it may be necessary to win the historic trophy in order for Mourinho to be safe in his job, and even then it may not be enough.
"The last title was not 20 years ago it was three years ago".
He also conceded it was sweet to triumph in a country where some critics claimed his purist principles couldn't flourish.
Few expected it to happen on Sunday.
City can finally call themselves champions in an official sense but that notion has been widely known for some time.
The consistency of Arsene Wenger's Invincibles has to be admired and they are still the only side to have gone through a Premier League season without losing.