Portsmouth got the better of Spurs' miserly defence in a deserved win.
Spurs had conceded just three goals before Monday, but Jacques Santini's side were unsettled by the strength and pace of Lomana LuaLua and Yakubu.
Just past the hour those two combined for the goal, LuaLua crossing for Yakubu who headed in from close range.
Anthony Gardner did hit the post for Spurs with a header but the visitors paid for Jermain Defoe's uncharacteristic wayward finishing.
Defoe's most glaring miss was an embarrassing miskick after a slick one-two with Robbie Keane.
Ironically Spurs' best period of attacking play came just before Yakubu's goal when Defoe threatened, but for most of the game Santini's side were pinned back in their own half.
One of the reasons for Spurs' impressive defensive record has been Paul Robinson's superb form and he was soon quickly into action.
The England goalkeeper managed to get a hand to Yakubu's low shot and although the ball ran to Eyal Berkovic, the Israeli sent his shot over the bar.
Robinson then saved Nigel Quashie's shot which bounced up in front of him.
Having demonstrated his quick reflexes, Robinson showed his bravery when he cut out Dejan Stefanovic
's header across the goal as Yakubu and
LuaLua bore down on the Spurs goalkeeper.
LuaLua's clever chip almost sent Yakubu clear but the chance went begging after the Nigerian miscontrolled.
Undeterred Yakubu worked an opening down the Spurs right, pulling the ball back for Berger, who flashed a shot over the bar.
On 63 minutes the persistence of LuaLua and Yakubu finally brought its rewards.
Quashie found LuaLua on the right with an intelligent pass and his cross was headed home from close range by Yakubu past Robinson's despairing dive.
In the first half, Spurs struggled to carve out many chances though a one-two between Defoe and Keane sent the England striker clear, only for him to inexplicably miskick at the last moment.
Berkovic was also guilty of a horrendous miskick soon after the restart when LuaLua cut the ball back from him following a wonderful run down the Spurs right.
The second half saw Spurs adopt a more positive approach, as Defoe looked to atone for his earlier miss.
Released by Simon Davies' pass, Defoe quickly unleased a shot that needed Shaka Hislop to adjust his feet after it took a deflection off David Unsworth.
The England striker also almost pounced on the rebound after Gardner's header hit the post following a Michael Brown free-kick, but Defoe was denied by Stefanovic's block.
Late on Defoe almost wriggled his way free, but he was finally halted by another superbly-timed Stefanovic tackle.
And in stoppage time Stefanovic was again on hand to get in yet another block, this time from a Johnnie Jackson shot.
Portsmouth: Hislop, Griffin, Primus, Stefanovic, Unsworth,
Faye (Cisse 85), Quashie, Berger, Berkovic (Fuller 55),
Yakubu (Kamara 75), LuaLua.
Subs Not Used: Ashdown, Taylor.
Goals: Yakubu 63.
Tottenham: Robinson, Pamarot, Naybet, King,
Gardner (Kanoute 72), Davies, Brown (Carrick 72), Pedro Mendes,
Atouba (Jackson 80), Keane, Defoe.
Subs Not Used: Keller, Ziegler.
Ref: U Rennie (S Yorkshire).