"Both sides were trying to win, and that's what I like to see," Mourinho said. "Maybe we got a bit lucky in the end, they had a good chance just before we scored, but in the whole match, I think we produced more chances to win than they did.
"We showed great focus, concentration and desire, and we were playing a quality team. When it went into the last few minutes, we knew a single defensive mistake might cost us the game, and in the end that was what happened to Spurs."
The Portuguese held a finger to his lips at the final whistle and muttered directly into the camera after their most important win of the season so far. "Some people speak too much," Mourinho said of the gesture. "You know, calm down, relax. Relax a little bit. Don't speak too much - speak, speak, speak. You know, relax."
Asked if it was aimed at the critics he labelled "Einsteins" or journalists, he said: "Yeah, relax a little bit. Don't be so nervous, don't be so excited. Calm down a little bit. The opposition bench did their job, super correct. It has yet to arrive, the match where myself, Mauricio [Pochettino], my staff and his staff, have a problem. We played against each other so many times since Spain, and we have a really good relationship. We lose, we win, I don't know if we draw and we are always correct with each other. And once more I'm even happier because we beat a very good team. I like the team very, very much."
Both sides employed similar formations with three central defenders, though Tottenham's three were that little bit better at playing out from the back. The visitors made better use of the ball all over the pitch throughout the first half, in fact, with Christian Eriksen, Dele Alli and Harry Winks all possessing a subtlety and invention in passing that the home side mostly lacked.
Spurs obviously missed Kane getting on the end of their best moves, though at least they were producing some moves and finding each other confidently. United were predictably stodgier; with Nemanja Matic and Ander Herrera occupying two of the midfield positions, Mourinho seemed to be relying on Henrikh Mkhitaryan to supply the creativity, with the result that Marcus Rashford and Romelu Lukaku were rarely brought into the game.
For all that, there was little danger of the deadlock being broken before the interval, Eric Dier made a good tackle in the area to stop Rashford in his tracks early on, and when the ball broke to Lukaku, he missed the target spectacularly, whether his intention was a shot or a cross. Rashford registered United's only attempt on target in the first half, with a free-kick from a long way out, and though Hugo Lloris dived to his right to save the ball looked to be going wide of the post anyway.
At the other end, Spurs' tidy approach worked tended to fizzle out by the time it reached Son Heung-min, notionally deployed as a striker, though Dier finally managed to bring a save from David de Gea on the stroke of half-time with a weakly hit shot. De Gea's goal had been in greater danger a few minutes earlier when he collided with Phil Jones in claiming a cross and spilled the ball, only for Moussa Sissoko to snatch at his brief chance and send his shot high into the Stretford End.
Spurs sent on Mousa Dembele to try and restore some midfield control, United responded with Jesse Lingard for Mkhitaryan and Martial for Rashford. The last was slightly surprising, since Rashford was probably the player causing the Spurs defence most problems, though Martial was almost instantly involved in helping set up a chance for Lukaku and the favour would be returned before the end. When Valencia went into the book for diving in search of a penalty, it began to look as if a goal would never arrive, yet both sides played their part in an eventful last 10 minutes. Alli ghosted on to a delightful diagonal ball from Eriksen, but could not quite get his feet in the right position to beat De Gea from close range, then at the other end, Lukaku struck the foot of a post with a header from Lingard's cross.
You would still have put money on a scoreless draw, but in the nick of time, United came up with a textbook route-one winner to confound their opponents. De Gea launched the ball upfield, Lukaku beat Jan Vertonghen to the first header, which left Martial running clear into the area to beat Lloris with a composed finish.