Two goals in the second half sealed their fate at the Eppleton Colliery Welfare Ground.
David Ferguson bundled home the opener after a scramble from a corner on 58 minutes with substitute Martin Smith's penalty doubling the home side's lead 20 minutes later.
Daniel Akindayini's last-minute reply gave us late hope of salvaging a point - and there were appeals for a penalty as Milos Veljkovic went down in the box in injury time - but Sunderland held on.
The Black Cats had the territorial advantage in the early exchanges and Luke McGee was forced to save at the feet of Connor Oliver on four minutes. Carl Lawson met the following corner cleanly but headed straight at McGee.
The home team's best chance of the half fell to Duncan Watmore as we failed to clear Thomas Robson's cross but McGee spread himself at the near post and made the block.
The lads grew into the game and started to create chances in the final 10 minutes of the half.
Alex McQueen's pass found Harry Winks bursting through in the left channel, the midfielder firing inches wide and Veljkovic had the strength to win Ryan Mason's inswinging free-kick only to head wide.
Left-back McQueen was involved again in the 43rd minute, bouncing a pass back to Akindayini who shot straight at Joel Dixon.
Sunderland opened the scoring eight minutes into the second half.
It all started with Watmore's burst forward into the box and a low shot turned wide by McGee. The corner was swung in to the near post, we failed to clear and Ferguson bundled home from close range.
Ugo Ehiogu made a couple of changes just before the hour with Nathan Oduwa and Filip Lesniak on for Emmanuel Sonupe and Harry Winks. Oduwa almost equalised immediately, cutting in from the right and shooting just wide. Carter-Vickers then got forward from right-back to meet Lesniak's cross but couldn't get enough power on his header.
Sunderland doubled their lead with 12 minutes remaining. Smith jinked into the box between Carter-Vickers and Veljkovic, was tripped and picked himself to take the penalty. McGee was unlucky, parrying away the initial spot-kick only for the ball to rebound straight back to Smith, who planted home for 2-0.
We almost hit back straight away as Miller fizzed in a shot from the left angle but Dixon got down to turn away.
We finally hit back in the last minute when Oduwa crossed from the right, Ferguson failed to clear and Akindayini slammed home from 10 yards.
There was one final fling in four minutes added time, Veljkovic went down under a challenge in the box but appeals were waved away.
Sunderland U21: Dixon, Cartwright, Robson, Oliver (Smith, 73), McNamee, Ferguson, Watmore, Agnew, Mavrias, Lawson (Greenwood, 82), Cabral (Robson, 90+3). Unused subs: Stryjek, Sukar, Greenwood.
Spurs U21: McGee; Carter-Vickers, Ball, Veljkovic, McQueen; Lameiras (Pritchard, 72), Mason, Winks (Lesniak, 59); Sonupe (Oduwa, 57), Akindayini; Miller. Unused sub: Miles.