A goal from Christian Eriksen after only 11 seconds and an own-goal from the unfortunate and inept Phil Jones set the tone on a night which was meant to be all about Sanchez’s league debut but turned, instead, into an inquest into the quality of players at the other end of the field — and a celebration of Tottenham’s growing maturity.
The result leaves United 15 points adrift of leaders Manchester City and now only three points ahead of third-placed Liverpool — with the only consolation being Chelsea’s shock home defeat against Bournemouth across London at Stamford Bridge.
“It’s a performance that starts with a ridiculous goal,” Mourinho fumed.
“That goal after a few seconds has a big influence in the game because Tottenham can play the way they like to play.
“In the end we played against a very good team. Both goals were ridiculous goals.
“A team to win matches needs to score goals and also defend well — on this occasion we were very bad.”
Tottenham, meanwhile, are now within touching distance of the Champions League places and with a belief that they deserve to be there.
“I’m very happy. Congratulations to the players. It was a great performance,” Spurs boss Spurs boss Mauricio Pochettino said.
Referring to Spurs’ brilliant start, Pochettino added: “We always try to be aggressive from the beginning. Our aim is to be focused from the beginning. It was massive to be up early in the game.
“Three more points puts us in a very good position to fight for the top four.”
With Sanchez painfully quiet, Spurs not only looked more assured in attacking areas but also exposed the defensive weakness of Jones, Chris Smalling, and Ashley Young, leaving many wondering why money has been spent in recent transfer windows on high-profile attacking talent at Old Trafford — but not on defenders of the same quality.
United were wide open for most of this match in which Tottenham created a string of excellent chances which should have resulted in further goals.
Make no mistake this was a deserved and well-constructed victory by Pochettino’s side who were also denied a clear-cut penalty in the first half and who ended it looking comfortable.
It is an important victory, too, for those in lily white. Until this match Tottenham had taken just three points from 15 in clashes against the ‘big six’, placing them bottom of that particular table, and they arrived at Wembley having being held to a draw by lowly Newport County in the FA Cup.
Even so, there was a vibrancy about Pochettino’s men which suggested they were ready to put that record right, and it took them only 11 seconds to do it.
United’s defence, clearly asleep from the kick-off, allowed a long ball forward to catch them out.
Jones, despite his size, allowed himself to be bullied by Tottenham’s Harry Kane as the striker knocked the ball down to Dele Alli, and he in turn found Eriksen — who finished smartly.
The goal marked Eriksen’s return to action after illness and his presence was a welcome boost for a team which, on its day, is now a match for anyone, despite the statistics which suggest otherwise.
Further chances were to follow as, time and time again, United’s defence were found out of position.
Son, for instance, volleyed wastefully wide from a long Dembele pass which caught out the visiting back four, before Spurs sprang the offside trap again — but Trippier failed to square to Son who was completely unmarked in the middle.
The second goal was equally embarrassing for a red-faced Mourinho as Spurs broke once more after 28 minutes and this time Trippier’s low cross was turned into his own net by the hapless Jones.
Spurs could, and should, have had a penalty after 31 minutes when Antonio Valencia clearly upended Alli, and the home side — backed by a Premier League record crowd of 81,978, missed a host of chances after the break too.
Son saw his effort saved by David De Gea when clean through while Kane, who for once didn’t have his shooting boots on, fired wide on three occasions.
Even when Mourinho finally lost patience, taking off both Paul Pogba and Jesse Lingard after 63 minutes in favour of Juan Mata and Marouane Fellaini, United’s fortunes did not improve.
Whereas in the first half they at least created chances — for Lingard who was clean through for example — they drifted badly as the match wore on. In fact, Fellaini only lasted a few minutes before being replaced by Ander Herrera, presumably because of injury, and Tottenham looked entirely in control.
For Sanchez, it must have felt eerily familiar. Wearing a red shirt, running around everywhere but finding your defence incapable of keeping a clean sheet under pressure.
United will hope his home debut, against Huddersfield on Saturday, brings better luck — and it should do. But this result provided an insight into just how far away United are from being title challengers — and gave Spurs, who now head to Liverpool, belief that top-six hoodoo is over. Victory at Anfield would really shake up the table — from second place down, at least.
Lloris 6, Trippier 8, Vertonghen 7, Davies 7, Dier 7, Eriksen 8, Dembele 7 (Wanyama 90), Sanchez 7, Alli 7 (Sissoko 88), Son 7 (Lamela 81; 6), Kane 7.
De Gea 7; Valencia 6, Jones 4, Smalling 5, Young 5, Pogba 6 (Mata 63; 6), Matic 6, Lingard 5 (Fellaini 63; 5; Herrera 70; 6; 6),Sanchez 6, Lukaku 6, Martial 5.