Pep Guardiola spent the day golfing.
They will nearly certainly still be relegated.
United was too narrow and predictable, with wide players Alexis Sanchez and Juan Mata constantly cutting inside and leaving the midfield congested.
Romelu Lukaku saw a header saved by Ben Foster in the second half but, other than that, United rarely threatened to score.
However, United's record £89m signing followed it up with a underwhelming display on the left of midfield in a 4-3-3 system.
Ultimately, Rodriguez was the saviour for West Brom, and the title-clincher for City.
West Brom's Jay Rodriguez cleared of alleged racial abuse
Manchester City manager, Pep Guardiola said he won't be watching Manchester United clash with West Brom tomorrow. Rodriguez headed home for West Brom , with United's 1-0 defeat seeing City seal the title without kicking a ball.
"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.
"It was a bad reaction after the City victory, the outcome of that is complicated football", Mourinho said. It is even more important for the next games and we know we have to compete until the last week. "One more touch to control the ball, one more flick, one more trick". The best team by a street, they entered 2018 14 points clear and never remotely looked like being caught. "And then to get second in the league which is not the ideal position, but it's the position we want to finish now".
Manchester City fans celebrate at Wembley Stadium during their 3-1 victory over Spurs.
Manchester City have defeated every single team this season in the Premier League - only the third time that a Premier League team have done this in a single campaign (Manchester United in 2010-11 and Chelsea in 2005-06).
In truth, that race was over a long time ago and it was a matter of time before City sealed the title. "Our City. Premier League Champions 17/18".
Manchester City captain Vincent Kompany on Sky Sports: We were consistent the whole season and were able to play at the level we were expected to perform at.
Despite the win for West Brom the layers remain convinced that they will be relegated to the Championship with no one willing to offer the minimum odds of [1.01] in the Relegation market.
United, meanwhile, will attempt to hold onto second place and automatic qualification into the Champions League group stages next season.