After a tense first half, Monday's game came alive in the second 45 minutes as Spurs ran riot against United's demoralised defence.
Harry Kane opened the scoring with a header 50 minutes into the match, and from there the floodgates opened.
Lucas Moura struck just two minutes later, and added his second of the match late on to seal a 3-0 victory which, following on from a 3-2 reverse at the hands of Brighton, piles the pressure on the shoulders of the Special One.
The game also marked a piece of unwanted history for Mourinho, who is battling to avoid the 'third season syndrome' that has dogged him throughout his career.
Never before had Mourinho seen one of his teams lose 3-0 in their own back yard, making Monday's drubbing his worst-ever home defeat.
But he will need to see an improvement soon having been condemned to another career low point.
For the first time in his 18 years as a manager, a Mourinho team has lost two of its first three league games - now all eyes are on the under-fire boss as he seeks to turn around his team's fading fortunes.