Maddison return inspires win
Tottenham have been on a poor run, but a large part of their form can be attributed to a string of first-team injuries.
Manager Ange Postecoglou will be thankful he was able to start playmaker James Maddison as well as goalkeeper Guglielmo Vicario, with both impressing on their returns.
Long-term absentees Brennan Johnson, Destiny Udogie and Wilson Odobert were also all fit enough to make the bench.
Spurs looked good going forward, with new signing Mathys Tel lively on his first league start since joining on loan from Bayern Munich. The 19-year-old Frenchman forced Onana into a low save after Son Heung-min's first-half cutback.
Dejan Kulusevski also went close with a similar effort midway through the second period.
But in midfield, Spurs struggled to assert control - and United regularly created opportunities to equalise which they could not take.
Tottenham and Postecoglou, though, will take a narrow win however it was earned, having picked up just four points from their previous eight league games.
Boosted by Maddison and Vicario they are now 12th in the table, moving above United.