Jermain Defoe's hat-trick sparked Spurs to a fourth successive win against a deflated Southampton team.
The England striker first slotted home Frederic Kanoute's cross and then coolly punished a defensive error.
Kanoute beat Southampton's offside trap to put Spurs three up but two minutes after the restart Peter Crouch's header gave Saints brief hope.
After Defoe completed his hat-trick there was still time for substitute Robbie Keane to score Spurs' fifth.
Crouch proved an early menace at a throw-in but there was nobody to cash in on his flick.
Southampton looked confident in the early stages but were rocked on their heels as Defoe fired Spurs ahead on eight minutes.
Danny Higginbotham and Darren Kenton both failed to cut out Michael Carrick's long ball down the right flank, Kanoute took advantage to run on and screw the ball back for the waiting Defoe, who made no mistake from eight yards.
Kanoute also got in on the goalscoring act
Saints had their first clear sight of goal on 15 minutes when Crouch knocked a cross into Kevin Phillips' path and Anthony Gardner got in a vital block.
Carrick was influential early on and he neatly side-stepped David Prutton to work himself space, but his weak effort was no test for Antti Niemi.
Southampton clawed their way back into the game and Higginbotham made ground to cross deep to the far post, where Mikael Nilsson gathered before flashing the ball just ahead of Phillips' lunge.
But back came Spurs and Defoe turned past Kenton, only to be denied by a brilliant point-blank save from Niemi.
Defoe made no mistake a minute later, though, when Prutton's tackle on Kanoute turned into a perfect pass for the England striker, who ran on to clip his shot past Niemi.
Spurs were playing with the confidence born of three successive wins and Niemi kept his side alive by launching himself to his left to paw away Kanoute's powerful shot.
Niemi was left exposed on 43 minutes when Carrick measured a ball over the top for Kanoute, who beat Southampton's offside trap and pulled the ball down before slotting past Niemi.
Spurs keeper Paul Robinson denied Southampton a lifeline in first-half injury time with a point-blank save from Crouch's shot.
Crouch gave Southampton the briefest glimmer of hope
Saints boss Harry Redknapp replaced Nilsson at half-time with fellow Swede Andreas Jakobsson, but strangely did not bring on James Beattie.
Within two minutes of the restart they pulled a goal back when Ledley King sliced Prutton's cross skyward and Crouch was underneath it to head home from four yards out as it dropped.
Prutton's run then produced a carbon copy error from Gardner and, as the ball hung in the air, Crouch appeared to be blocked by King.
Any hopes of a Southampton fightback were strangled as Defoe completed his hat-trick. Michael Brown cashed in on another defensive error and although Niemi blocked his shot Defoe was on the spot to bury the loose ball.
Southampton's miserable afternoon was rounded off when the rot set in on Niemi, who allowed substitute Keane's close-range effort to squirm under his body.
Tottenham: Robinson, Pamarot, Gardner, King, Atouba,
Ricketts (Pedro Mendes 66), Carrick, Brown, Ziegler (Keane 83),
Subs Not Used: Redknapp, Davenport, Fulop.
Goals: Defoe 8, 27, Kanoute 44, Defoe 61, Keane 88.
Southampton: Niemi, Dodd (Folly 54), Lundekvam, Kenton,
Higginbotham, Nilsson (Jakobsson 45), Telfer, Prutton,
Anders Svensson, Phillips, Crouch.
Subs Not Used: Beattie, Smith, Fernandes.
Booked: Lundekvam, Prutton.
Goals: Crouch 47.
Ref: P Dowd (Staffordshire).