Son Hueng-min and Harry Kane scored twice, with Tanguy Ndombele and Serge Aurier also on target as 10-man United suffered their worst defeat since they were memorably hammered 6-1 at home by Manchester City in 2011.
It meant it was not only the heaviest defeat since Ole Gunnar Solskjaer took temporary charge in December 2018, but also the largest United have suffered since Ed Woodward took over as executive vice-chairman in 2013.
The result leaves United 16th in the Premier League table, with newly promoted Fulham and West Brom the only clubs with a worse goal difference. Only West Brom have conceded more than their 11 goals.
United were completely outplayed, even before they were reduced to 10 men midway through the first-half when Anthony Martial dragged his hand across Erik Lamela’s face in reaction to an elbow in his neck.
In contrast, Tottenham moved up to fifth after emerging from a packed schedule of five games in 11 days in three competitions with a creditable four wins and a draw.