Torrential rain prior to kick-off led to a 30-minute delay and a reduced match of two halves of 40 minutes.
Gylfi Sigurdsson struck first 27 minutes into the game after fine work by Kyle Walker on the right wing, but Cabral equalised soon after with a composed finish past Gomes.
Sunderland went ahead when Wes Brown climbed highest to head home from a corner and David Moberg Karlsson completed the scoring with the third in the last minute.
It means we now face South China FC in the third/fourth place play-off on Saturday, kicking-off at 11am UK time (6pm local). Manchester City beat South China 1-0 and will face Sunderland in the final.
After the delay as heavy rain swept into the Hong Kong Stadium, both sides emerged to a rapturous reception from fans.
And despite the conditions, the teams came out looking committed and hungry for the win with Andre Villas-Boas employing a 4-3-3 formation with Clint Dempsey on the left, Aaron Lennon on the right and Emmanuel Adebayor in the centre.
Sigurdsson went close to opening the scoring inside a minute with a 25-yard free-kick that flew just wide of Vito Mannone's post.
The unforgiving nature of the pitch reared its ugly head minutes later when Steven Caulker misjudged the bounce of the ball on the mud allowing Stephane Sessegnon to race through on goal, Michael Dawson getting back quickly to block the Senegalese player's shot.
Conditions continued to deteriorate but we deservedly took the lead after 27 minutes.
Walker raced down the right, beat his man and drilled a ball across the box from the byline to Sigurdsson whose deflected effort from 14-yards out beat Mannone.
Unfortunately, the lead would last only five minutes.
Jozy Altidore took a delightful touch to play the ball into the path of Cebral who slid a shot into the corner of the net as the first half ended 1-1.
Sunderland should have taken the lead immediately after the break when Altidore, an increasingly large influence on the game, swivelled and scuffed a shot into substitute Brad Friedel's arms from only six-yards out with the goal gaping.
Jan Vertonghen, a half-time substitute, had only been on the pitch for eight minutes when he fell awkwardly and needed lengthy treatment before Zeki Fryers replaced him and play resumed.
Mannone made two terrific saves as we looked to retake the lead - first from Adebayor's curler, then a magnificent close-range stop from Defoe after the striker turned and shot in trademark style - but it was Sunderland who would score the next goal.
Substitute Karlsson swung in a corner and Brown held off the challenge of Fryers to head home from just outside the six-yard box, a goal against the run of play.
As we searched for a way back into the match space opened up for the Sunderland attack to run into and Altidore forced two diving blocks from Friedel as Di Canio's men searched for a killer third goal.
It almost came when Wickham's header looked to be headed for the top corner of the goal, only for Friedel to claw the ball away at full stretch leaving the striker looking stunned.
But Sunderland were not to be denied, Karlsson completing the scoring after latching onto a long ball and sliding his shot across Friedel into the far corner of the goal on the stroke of full-time to complete the match.
Spurs (4-3-3): Gomes (Friedel, 41); Walker, Caulker (Vertonghen 41; Fryers, 51), Dawson, Rose; Huddlestone (Carroll, 70), Lennon (Defoe, 41), Parker; Dempsey (Townsend, 70), Sigurdsson, Adebayor. Unused subs: Lloris, Assou-Ekotto, Naughton.
Sunderland: Mannone, Brown (Roberge, 76), Cabral, Larsson (Ba, 62), Gardner, Johnson (Karlsson, 62), Colback, O'Shea, Altidore (Wickham, 74), Sessegnon, Giaccherini (McClean, 77). Unused subs: Pickford, Westwood, Vaughan, Mandron, Cuellar, Roberge.
Goals: Spurs - Sigurdsson (27). Sunderland - Cabral (33), Brown (63), Karlsson (79).
Referee: Mr Lui Kwok Man (Hong Kong).