So, what went wrong for the Red Devils? I was not going to celebrate like insane, for me we should play with great focus and intensity and try and kill the top four situation and be more stable in second.
Despite the victory, West Brom are stuck at the bottom of the table with 24 points.
"We were masters in complicated football, everything was complicated", said Mourinho.
United manager Mourinho had long given up hopes of winning the title, instead focusing on finishing second.
Jose Mourinho's charges had the rhythm and tempo on their side after half-an-hour and looked increasingly unsafe whenever they were on attack.
It is hard to imagine United would have approached a home game against the bottom club, particularly in the first half, in such a way under Sir Alex Ferguson's management.
"I don't think we deserve to lose, but we gave them the opportunity to win the match", he added.In the Premier League, anybody can defeat anybody.
Jay Rodriguez scored in the 73rd minute off of a corner. The Frenchman attempted to chip Foster on 38 minutes, but the ball cleared the bar, and he saw a shot from inside the D deflected over by Ahmed Hegazi in stoppage time. "They are fighting for survival but there's no excuses".
From first look at the match facts, one would scratch their head because United dominated in nearly every category. Right in the beginning of the campaign, after scoring 10 goals to get three consecutive victories with clean sheets, they drew 2-2 against Stoke City. Simply, Manchester United just got unlucky.
Foster impressively denied Lukaku when meeting a clipped Matic cross and Lingard had an attempted deflected wide as a goal looked inevitable. West Brom, to their credit, also kept probing forward but they lacked the class required to really open United up at the back. We didn't' create enough chances.
"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 title is the fifth overall top division win in the club's history (1936-37, 1967-68, 2011-12, 2013-14, 2017-18).
"It's something special. A derby win at this point in the season is a highlight", Schalke sporting director Christian Heidel said.
Manchester City have became the Premier League champions.
The defeat for United has also slightly reopened the fight for second as they remain one point ahead of Liverpool in third place, albeit with a game in hand.