Les Ferdinand's winner kept alive Spurs' slim hopes of a European place through the Premiership - and pushed Sunderland further towards danger.
Ferdinand followed up Gus Poyet's opener with a 62nd-minute goal to ease Spurs' anxieties after they had created and spurned a series of chances.
And although Cameroon striker Patrick Mboma repaid Sunderland manager Peter Reid with a goal in his first Sunderland start, the pressure continues to mount on the Sunderland boss. After this latest reverse his side are just five points ahead of the relegation places.
Reid saw Mboma show up well in the opening stages, setting up Kevin Phillips to shoot wide.
At the other end, Teddy Sheringham fired straight at keeper Thomas Sorensen, while Christian Ziege curled a 30-yard free-kick over the bar after Sheringham had been hauled down by Jody Craddock.
Spurs continued their bright start and Poyet almost gave them the lead with a cheeky backheel from Ziege's cross which Sorensen saved.
Mboma showed his penalty box prowess by powering a diving header narrowly wide, while Ferdinand again broke powerfully, only for Joachim Bjorklund to block with a timely challenge.
Spurs took the lead on 31 minutes, taking advantage of the defensive sloppiness that has typified Sunderland's slide down the table as Poyet stole in unnoticed to bundle in Ziege's corner.
Spurs missed chances to double their lead, with Sheringham firing over from six yards with only Sorensen to beat, and then Ziege heading over from a similar distance.
Mboma made Spurs pays for those misses in the third minute of first-half injury time. Unselfish
He got the better of Ledley King as he chased Bernt Haas's long ball to stroke the ball past Neil Sullivan.
Sunderland suffered a blow 13 minutes into the second half when Bjorklund limped off with a hamstring injury.
Moments later, Sunderland were furious after being denied a penalty when Mboma appeared to be pulled down by Dean Richards.
Spurs continued to create and miss chances, with Sheringham and Poyet both heading over when well-placed.
Tottenham's frustrations were banished on 62 minutes when they regained the lead.
Ziege cut in from the left, and after drawing Sorensen unselfishly, squared the ball for Ferdinand to tap in.
Sheringham tried his luck from another 25-yard free-kick after 67 minutes and although his shot was on target, it was comfortable for Sorensen.
In a desperate attempt to find an equaliser, Reid threw on Niall Quinn in place of Mboma, but Spurs held out.