A goal from Christian Eriksen inside 11 seconds set Spurs on their way to another Wembley victory.
The Dane pounced when the ball ran loose after Dele Alli had an effort blocked following a knock-down from Harry Kane.
Phil Jones, under pressure from Kane, fired a Kieran Tripper cross into his own net after 28 minutes to double the lead, and it was no more than Spurs deserved after a first half full of verve and energy.
Hugo Lloris made some important blocks to deny United a path back, but Spurs always looked comfortable, with their pace and movement making the visitors look ordinary.
There might have been further goals for a rampant Spurs after the break, with Eriksen, Alli, Kane and Son Heung-Min all taking turns to pepper David de Gea with shots.
United’s malaise was summed up by Jose Mourinho’s withdrawal of Marouane Fellaini in the second half, just six minutes after sending the Belgian on.
And Alexis Sanchez was easily contained on his first return to the capital in a United shirt on a woeful night for the visitors in front of a new Premier League attendance record of 81,978.
Tottenham: Lloris; Trippier, Sanchez, Vertonghen, Davies; Dier; Eriksen, Dembele (Wanyama 90), Alli (Sissoko 87), Son {Lamela 80); Kane. Subs not used: Vorm, Rose, Llorente, Walker-Peters.
This post was last modified on 31/01/2018