The Republic of Ireland international inadvertently turned Moussa Dembele's 50th-minute cross past keeper Vito Mannone to hand the visitors the points and leave the Black Cats deep in trouble at the foot of the Barclays Premier League table.
It was the fifth time this season a Black Cats player had put through his own goal, more than any man in red and white has achieved at the other end.
Defeat was all the more galling as the home side, just as they did against Chelsea in midweek, took the lead when Adam Johnson capitalised on keeper Hugo Lloris' blunder to score his first league goal of the season.
But Paulinho levelled within six minutes and Spurs never looked back, and had their finishing been better - Jermain Defoe twice hit the post and fired wide when through on goal - they would have won far more comfortably.
However, Sunderland were convinced they should have been awarded a 75th-minute penalty after substitute Sandro appeared to block Sebastian Larsson's corner with his arm.
Villas-Boas arrived on Wearside yet to convince his critics he is the right man for the job, but with opposite number Gus Poyet facing a very different challenge.
Crystal Palace's victory earlier in the day had done Sunderland few favours, although they were mathematically no worse off as they attempted to close a five-point gap to West Ham just above the relegation zone.
Poyet, who has challenged his players to double their points tally by the end of the calendar year, opted to start with both Jozy Altidore and Steven Fletcher, although he asked the United States international to play in a slightly withdrawn role in front of a narrow midfield trio.
However, that simply served to congest the midfield and playmaker Ki Sung-yueng found himself pinned back inside his own half with little scope to open up the visitors.
Spurs enjoyed the space they were afforded out wide but were able to make little of their share of the possession in a tepid opening to the game.
Paulinho eventually injected some excitement with a dipping, swerving 13th-minute shot which flew just over and, after Mannone had turned Lewis Holtby's curling effort around the post, saw another close-range attempt blocked by Wes Brown after he had run on to Defoe's clever pass.
In the meantime, Jack Colback had wasted good work by Fletcher and Altidore by firing high and wide, and the Black Cats might have been made to pay as Nacer Chadli and Defoe both went close within seconds.
However, it was the home side who took the lead with eight minutes of the half remaining when Lloris made a mess of collecting Ondrej Celustka's cross and Johnson controlled the loose ball before blasting it into the roof of the net.
But the lead lasted just six minutes, Paulinho stabbing home the equaliser after Chadli had headed Holtby's deep free-kick back across the six-yard box.
Celustka tested Lloris from distance on the stroke of half-time but this time the Frenchman was equal to the task.
Tottenham needed just five minutes of the second half to get their noses in front, although they did so with a touch of good fortune.
Dembele's powerful run took him past Colback's ineffectual challenge and his cross cannoned off O'Shea and past the unfortunate Mannone.
Johnson's last-gasp intervention denied Holtby a 53rd-minute tap-in and Brown blocked a goal-bound effort from the same man three minutes later with Spurs going for the kill.
But the visitors were unfortunate not to extend their lead with 57 minutes gone when Chadli played Aaron Lennon in and Defoe headed his cross against the post.
Paulinho passed up a glorious opportunity to make it 3-1 on the hour when he missed his kick after Lennon had drilled the ball across the face of goal, and Defoe was just as profligate after being played in by Holtby six minutes later.
Fletcher sent an ambitious 71st-minute header wide as Sunderland tried to respond and he and his team-mates were left appealing in vain for a penalty after Larsson's corner was blocked by Sandro with more than a hint of an arm being used.
Defoe struck the upright for a second time with 11 minutes remaining and substitute Fabio Borini fired straight at Lloris at the other end three minutes later, but there was to be no late drama despite flurries of activity at both ends.