It was City's third title in seven seasons and easily its most convincing, with Pep Guardiola's team 16 points clear and still having five games to play this season. City's other two Premier League triumphs, in 2012 and '14, were sealed on the final day.
Second-place United dragged the title race out for at least another week by winning 3-2 at City last weekend, only to gift the trophy to City by losing to a team that is destined for relegation and had just one league win since August.
Guardiola might not have seen Jay Rodriguez's 73rd-minute winning goal at Old Trafford because he was due to be playing golf with his son instead of watching the match.
"Our Time. Our City. Premier League Champions 17/18," City tweeted soon after the final whistle, when the fifth English top-flight title of its history was assured.
Instead of City likely clinching the title at home to Swansea next weekend, that game at Etihad Stadium will now be a party and a celebration of one of the Premier League's finest teams which could yet break a slew of records by the end of the season.
An 18-match winning run from late-August to late-December laid the platform for the runaway title victory, and it was only a matter of when it would be clinched.
Few - including Guardiola - expected it to happen on Sunday.
"We've won you the league, Manchester City, we've won you the league," sang West Brom's fans near the end of the game.
The 2012 title win had the infamous last-gasp goal by Sergio Aguero. Six years later, the finale was much more underwhelming, with Rodriguez nodding in from a corner to silence the majority of Old Trafford and set up one of the most surprising wins of the season.
United manager Jose Mourinho had long given up hopes of winning the title, instead focusing on finishing second. This result left his team one point clear of third-place Liverpool, with a game in hand.
As for City, it has a month to finish a season with the most points, goals and wins in a single Premier League campaign.
Even more alarming for their rivals, though, after Manchester United's 1-0 loss to West Bromwich Albion on Sunday sealed City's triumph is that Pep Guardiola's latest fabulous creation may only be at the dawn of a potential new dynasty.
A new era?
Yet, even if City's season has already been a majestic success, what with a League Cup triumph and winning the Premier League with a record-equalling five matches to spare, a better measure will only come by the end of next season.
For no English champions have successfully defended their Premier League crown since City's once lordly neighbours United won the title for a third straight season in 2008-09.
That side, guided by Alex Ferguson and featuring Cristiano Ronaldo and Wayne Rooney in their pomp, completed a remarkable three-year spell, also featuring a Champions League win, another final appearance and a Club World Cup triumph.
This is the deafening level of dominance that the team once famously derided as "noisy neighbours" by Ferguson will now be out to cement after what could still end up as an unprecedented 100-goal, 100-point season.
The last decade, though, suggests back-to-back successes will be no given. Ferguson's last United triumph in 2012-13 was by 11 points from the then champions City; the following season, under new management, they finished seventh.
Jose Mourinho's 2015 Chelsea side won the league handsomely but could only finish 10th the following campaign. Last season's champions, Chelsea, look unlikely to be in the top four this year.
Yet if any team look capable of bucking this trend, it is Guardiola's latest potential masterpiece, which, remember, is still a work in progress.
He won both La Liga, with Barcelona, and the Bundesliga at Bayern Munich three years in succession, changing attitudes in both the Spanish and German game with the sort of possession-based pass mastery at pace that some believed would be stifled in England. That theory has been wholly debunked.
Certainly, Liverpool's heroics in both the Champions League and Premier League, swarming all over City for three victories this term, and Manchester United's 3-2 comeback win at the Etihad which delayed the coronation, dented the aura.
Those performances offered others a blueprint of how to knock City out of their aristocratic stride, yet still this could not hide the extent of their overall dominance.
Continental success
The dynasty will only be built on European success, though, and after the quarter-final exit to Liverpool, City's owners, who want a gilded continental powerhouse to match United's global lustre, will demand it and back those demands with huge funding.
Guardiola's talent and commitment is the key to this.
City's fans must have been left with soaring hearts on hearing how the Spaniard, in the second of a three-year deal, had talked of his long-term ambitions to make City's name resonate more in global terms.
"(Manchester City) does not have a history behind it at the level of titles but it does have the desire to become winners," he told a South American TV company.
"I do not rule out continuing to lead in 10 years. It will depend how I feel and if they want me."
Of course, they will want him. Every club does. His imprint in just two seasons has already been immense, vastly improving youthful talent like Raheem Sterling, John Stones, Leroy Sane and Gabriel Jesus, none of whom are older than 23.
Key men Fernandinho and David Silva are in their thirties now but much more can be still be expected of Ilkay Gundogan and Bernardo Silva alongside Kevin de Bruyne, the league's outstanding player this season.
"We need titles in Europe," Guardiola concedes. "After what this club has done in the last ten years, in terms of creating facilities and making it bigger, it will happen.
"But you need time. It might be next season or the season after that but it will happen, soon it will happen."
Guardiola sounded like a man who will be there when it does.
