The Red Devils came from 2-0 down to win 3-2 at Manchester City earlier this month to deny the Citizens the top-flight crown.
Goals from Paul Pogba and Chris Smalling secured a sensational turnaround at the Etihad Stadium to inject some positivity into their campaign.
However, Manchester United lost 1-0 to 20th-placed West Brom in their Premier League meeting at Old Trafford following Jay Rodriguez’s 73rd-minute goal.
As a result, the Red Devils humiliating handed Manchester City the Premier League title with five games to spare in the 2017-18 season.
Manchester United haven’t won the Premier League title since 2013 when Sir Alex Ferguson won the top-flight crown in his final campaign in charge.
David Moyes and Louis van Gaal failed to come close to glory following their subsequent appointments before Manchester United turned to three-time Premier League winner Mourinho.
Speaking to the club’s website, Manchester United boss Mourinho outlined what the Red Devils need to improve to win the Premier League crown next term.
“You don’t win titles with inconsistency,” Mourinho said.
“You win titles with quality, of course, and without quality you have no chance.
“But you also win titles with consistency. That is consistency at every level and not just the performance level, but day by day everything must be consistent from day one until the last day.
“So one of the things we have to improve is consistency.”
Manchester United are in second place in the Premier League table and a point ahead of third-placed Liverpool FC.
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