Mourinho said United, who are four points ahead of third-placed Liverpool who have played one more game, have to be cautious of their opponents who are desperate to secure points in a bid to ensure top-flight survival.
Manchester United play the bottom team in the Premier League on Sunday afternoon and even though there seems to be a general acceptance that West Brom are as good as relegated, José Mourinho is taking no chances.
The France worldwide has blown hot and cold at Old Trafford this term but produced an unforgettable performance in last weekend's Manchester derby to help the Red Devils overturn a 2-0 deficit to win 3-2.
Manchester United's French midfielder Paul Pogba celebrates scoring their second goal to equalise 2-2 during the English Premier League football match between Manchester City and Manchester United at the Etihad Stadium in Manchester, north west England, on April 7, 2018.
Yet they still clinch the trophy with five games to spare - a joint-Premier League record - after dominating the division for most of the campaign.
Inevitably, it will be the failures of this City team that will irritate Guardiola and his players, at the same time offering the critics the opportunity to find fault.More news: Unnao rape case: Accused Kuldeep Sengar's goons threaten villagers, alleges victims's uncle
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Will United be able to topple their rivals next season and win back bragging rights in the city?
"The performance was incredible, especially in the second half when we were losing 2-0 against the future champions, a team that didn't lose any Premier League match at their stadium".
Pogba started his occupation at United nevertheless moved to Juventus because of he felt first-team posssibilities have been restricted at Earlier Trafford.
"They won the title because they were the best team".
"Maybe also Manchester City will invest heavily and they don't let the others close the gap to them, I don't know".