On a remarkable afternoon at the Stadium of Light, Bent struck after just 34 seconds and then with a 29th-minute penalty to take his tally for the season to 23, 22 of them in the Premier League.
However, he twice spurned the chance to complete a hat-trick when Spurs keeper Heurelho Gomes saved further spot-kicks either side of the break.
The misses might have proved costly when Peter Crouch reduced the deficit with a 72nd-minute header just seconds after coming on, but fellow newcomer Bolo Zenden blasted home a superb volley four minutes from time to end Spurs' run of five successive Premier League victories and all but mathematically assure his side of another season in the top flight.
Bruce admitted in the run-up to the game that the game would be all about Bent, who left Spurs last summer on less than friendly terms.
He could not have known how prescient his comments were, however, as the England international put his former employers to the sword.
The game was just 34 seconds old when his predatory instincts came to the fore, pouncing on the loose ball after Gomes could only parry Fraizer Campbell's header and firing into the empty net.
Inevitably, his strike came in front of the travelling supporters packed in behind Gomes' goal, and they were given a second chance to witness his potency with the game just 29 minutes old.
This time, it was Steed Malbranque who tested the keeper from the edge of the box, and although he was up to the task, full-back Kyle Walker handled as he attempted to mop up and referee Lee Mason pointed straight to the spot.
Bent thumped the ball low to Gomes' right to establish a 2-0 lead, and he should have completed his hat-trick four minutes before the break.
Campbell surged into the box from the right and went over Luka Modric's out-stretched leg, and again Mr Mason was convinced, although the penalty award looked generous.
This time, Bent went to the keeper's left and Gomes got across well to turn his effort away, much to the delight of the beleaguered Spurs fans behind the goal.
Sunderland were worth their half-time advantage after enjoying much the better of the opening 45 minutes with strikers Roman Pavlyuchenko and Eidur Gudjohnsen seeing little of the ball.
Their only effort of any note came when winger David Bentley met Gareth Bale's cross with a downward header, but Sunderland keeper Craig Gordon was equal to the task.
Spurs boss Harry Redknapp made a double change at the break when he replaced Benoit Assou-Ekotto and Bentley with Niko Kranjcar and Jermain Defoe.
The changes would have paid dividends within five minutes had it not been for Gordon's continuing run of excellent form.
The striker broke free and attempted to beat the keeper with the outside of his right foot, but the £9million man stood tall to block his effort.
Gordon then turned Bale's flicked header from the resulting corner over the bar, but the impetus was firmly with the visitors.
Defoe did beat the keeper, but also the far post, with a 54th-minute shot across the face of goal, and Luka Modric forced a good save six minutes later.
But the home side should have had the points sewn up when they were awarded a third penalty for Wilson Palacios' trip on David Meyler.
Bent, who was berated by Bruce earlier in the season for allowing strike-partner Kenwyne Jones to take a spot-kick, this time rejected Malbranque's appeals, only to see Gomes save again with the help of his right post.
Crouch replaced Pavlyuchenko with 19 minutes remaining and made his mark within seconds, heading home Kranjcar's cross as the home side's appeals for a foul were waved away.
Bruce replaced Bent with Jones 12 minutes from time, and the substitute should really have made it 3-1, but completely missed his kick in front of goal after being picked out by Campbell, and Zenden's follow-up was cleared off the line by Younes Kaboul.
But the Dutchman, who had come on for Malbranque with 12 minutes remaining, was not to be denied a second time as he guided an exquisite late volley into the top corner.