Spurs were lucky not to find themselves 1-0 down after a goal from Edinson Cavani was overturned, with Son Heung-Min adjudged to have been fouled by Scott McTominay. Moments later, Spurs' best move of the first half saw the attack string a succession of quick passes together that culminated in Son adding the finishing touch to a Lucas Moura cutback in the 40th minute.
Lackadaisical defending allowed Cavani to find space behind enemy lines too regularly, though, and that eventually punished Mourinho's side as Fred rebounded an effort from the forward into the back of the net to equalise. Cavani then struck again after Sergio Reguilon was nutmegged to allow a cross to find the United No. 9. The home side didn't offer much in form of a response, and it was the away side who wrapped up the game courtesy of a Mason Greenwood goal in added time.
Spurs were able to get into some good counterattacking positions and looked dangerous when getting the ball out wide to Lucas and Son, but the north London club simply couldn't do it regularly enough against a strong defensive performance from Ole Gunnar Solskjaer's side.
Spurs often played at a pedestrian tempo with rarely more than one player making any movement off the ball. As a result, Mourinho's side struggled to create opportunities from any build-up play, registering just a single shot on target in the first half. They were also disorganised defensively, with Cavani allowed to run into dangerous situations all too frequently.
Manager rating out of 10
5 -- The Tottenham manager read the game well and introduced Moussa Sissoko at just the right time as United took charge of the match, but the team's approach was unclear in this game; the selection was positive with a number of the more attacking players starting, but Dean Henderson's goal was rarely threatened.
Player ratings (1-10; 10 = best, players introduced after 70 minutes get no rating)
GK Hugo Lloris, 7 -- The French goalkeeper was alert to United efforts after not having to face a shot on target in the first half, and he was unlucky to concede from a rebound from Fred. Cavani was then given too much space to give the visitors the lead late in the second half.
DF Serge Aurier, 6 -- Frequent runs down the right-hand side provided space for attacking players to operate in, but Aurier could have been better defensively with some of United's best attacks coming from his side.
DF Eric Dier, 5 -- Dier could have counted himself lucky after allowing Cavani to sneak in behind for United's disallowed goal but the Uruguay international continued to punish Dier, with the English defender too slow to react on too many occasions. The centre-back's concentration and alertness were non-existent at times.
DF Joe Rodon, 7 -- He dealt with balls that came into the box and likely stopped a goal when cutting out a cross destined for Cavani in the six-yard box. The young defender looked the more experienced of the two centre-backs for Spurs.
DF Sergio Reguilon, 5 -- The Spanish full-back offered a regular outlet down the left flank when transitioning the ball from defence to attack. Defensively, Reguilon could have done much better in the second half, but Spurs left him isolated when dealing with overloads. Struggled to cope with Greenwood.
MF Pierre-Emile Hojbjerg, 6 -- He battled well in midfield, which made it difficult for United to create much through the middle of the park. However, he was unable to establish as much authority on the game as seen in the previous match between these two sides at Old Trafford.
MF Tanguy Ndombele, 7 -- He was vital in the build-up to the Spurs opener after an incisive pass transitioned the ball into the danger zone in a play that eventually found Son at the back post. The French midfielder was Spurs' brightest midfielder and looked to play positively despite a lack of movement at times from the players in front.
MF Giovani Lo Celso, 6 -- He couldn't get into the game, the creative Argentine unable to threaten the United defence. Replaced by Sissoko on the hour mark.
FW Lucas Moura, 7 -- Looked positive and showed astute attacking positioning to find space behind Luke Shaw throughout the game, which paid off when cutting the ball back for Son for the opening goal. A good performance from the Brazilian, who made the best he could from a handful of Spurs counterattacks.
FW Son Heung-Min, 7 -- Son worked tirelessly but couldn't create much with United looking to double up on the Tottenham winger. Good movement late in the first half saw Son finish from Lucas' cutback.
FW Harry Kane, 6 -- Some good link-up play helped Spurs in the few chances they created but the English forward was unable to threaten Henderson's goal. Kane was kept quiet, for the most part, but didn't benefit from a sluggish Spurs attacking display.
MF Moussa Sissoko, 6 -- He helped combat United's brightest spell in the second half, which saw Mourinho's side pinned back into their own box.
MF Erik Lamela, N/R -- Lamela looked to get on the ball and play passes forward but there wasn't enough movement from Spurs; a theme consistent throughout the game.
FW Gareth Bale, N/R -- Spurs rarely looked threatening but for their goal, and there was not much Bale could do to change the game.