Anthony Martial struck late to give Manchester United a 1-0 victory over Tottenham at Old Trafford on Saturday.
Having lost for the first time in the Premier league this season at Huddersfield a week ago, United needed a victory to keep the pressure on leader Manchester City, which can re-establish a five point lead with victory at West Bromwich Albion later Saturday.
Tottenham struggled without leading scorer Harry Kane, who missed the game with a hamstring injury, but almost held out until United's sustained pressure told 10 minutes from the end.
Despite the absence of Kane, Mourinho's respect for Tottenham was evident in his team selection as he deployed three central defenders, matching the visitor's formation.
The sides canceled each other out for much of the first half with United coming closest through Marcus Rashford's free kick, which Hugo lloris did well to tip around the post.
United emerged with greater intent after halftime and was only prevented from taking the lead in the 55th minute by a fine clearance by Ben Davies after lloris spilled Henrikh Mkhitaryan's effort.
The home side continued to press and Antonio Valencia came close shortly after the hour-mark as his half-volley rose just above the Tottenham crossbar.
After a raft of substitutions from both managers the game appeared to be petering out, but the best action was saved until last.
With 13 minutes to go, the significance of Kane's absence was shown when Dele Alli missed Spurs' best chance of the game as he failed to volley Christian Eriksen's inch-perfect cross on target from just six yards out.
Within two minutes United almost took the lead at the other end as Romelu lukaku headed Jesse lingard's cross onto the post, before the deadlock was finally broken in the 81st.
lukaku's head was crucial once more as he directed David De Gea's clearance into the path of substitute Martial, who sent his shot across lloris and into the bottom corner.
City beat west brom 3-2
WEST BROMWICH: Manchester City equaled the best start to a Premier league season as it defeated West Bromwich Albion 3-2 on Saturday.
City has 28 points from its opening 10 games, matching its own performance under Roberto Mancini in 2011 and Chelsea's record in 2005. Both of those sides went on to win the title.
Goals from leroy Sane, Fernandinho and Raheem Sterling were enough to secure an eighth consecutive league victory for Pep Guardiola's side.
However, City appears to be taking nothing for granted at the moment as it produced another scintillating attacking display to restore its five-point advantage over second-place Manchester United.
Elsewhere, Arsenal came from behind to defeat Swansea 2-1 and move within a point of Tottenham.
liverpool brought Huddersfield back to reality with a 3-0 victory at Anfield.
Stoke secured a much-needed three points by beating Watford 1-0, and West Ham held on to draw 2-2 against Crystal Palace.