West Ham defender Anton Ferdinand headed a stoppage-time equaliser as Tottenham paid a high price for a sloppy second-half performance as the sides finished one goal each.
The England Under-21 centre-back levelled up for the visitors at White Hart Lane with time fast running out.
Tottenham were nowhere near their best in the London derby but Egyptian striker Mido's fourth goal of the season in the 16th minute looked enough to clinch all three points - until Ferdinand's late rescue act.
Shaka Hislop, the veteran goalkeeper who was too easily beaten for Mido's goal, came downfield for a corner given away by Michael Dawson but was not needed as Ferdinand surged into the six-yard box to nod the ball home.
It was just about the right result as West Ham never gave up on their task. Perhaps it would have been different but for Tottenham manager Martin Jol's surprise decision to leave former Hammers striker Jermain Defoe on the bench for all but the last 10 minutes.
Tottenham put their neighbours through a nervous opening with Edgar Davids striking a deflected drive from 25 yards just wide, before a fine pass by Michael Carrick was helped on by Jermaine Jenas to Robbie Keane whose low cross was cut out by Shaka Hislop.
But in West Ham's first serious attack after 10 minutes, Hayden Mullins was just off target with a shot from the edge of the area which appeared to beat Paul Robinson's dive.
And, a matter of seconds later, Yossi Benayoun's whipped attempt on goal curved past the left post with the England goalkeeper again struggling to make up ground.
Tempers flared on the quarter-hour mark when Tottenham's Teemu Tainio crashed into the advertising boards after a slight nudge by Paul Konchesky.
Tainio ran at the former Tottenham loanee, suggesting he should be booked, but referee Alan Wiley made do with a talking-to for both players.
Within a minute, West Ham were behind.
Dawson lobbed a long pass from his own half to the edge of the West Ham area where Mido nipped in between two defenders and lofted his header over a stranded Hislop.
Hislop, just back from World Cup qualifying celebrations with Trinidad and Tobago, and preferred to the fit-again Northern Ireland star Roy Carroll, looked stunned and his positioning had to be questioned, but his entire defence had dropped off, leaving him cruelly exposed.
Tottenham cranked up the pressure.
Tainio's shot was blocked before former Tottenham hero Teddy Sheringham, skippering West Ham, clashed with Davids after the Dutchman's clattering tackle. Sheringham appeared to grab hold of Davids and after a brief flare-up Wiley showed the yellow card to both in the 22nd minute.
Another terrific pass by Carrick put Mido away on the left soon afterwards but his cross produced a total mis-hit by Jenas inside the area.
And after 19-year-old Mark Noble, replacing injured skipper Nigel Reo-Coker in the West Ham midfield, had a goal disallowed for offside, Carrick curled a free-kick just over at the other end.
There was little doubt that Tottenham had edged an exciting first half but, apart from the aberration for the goal, West Ham's defence looked solid in the opening 45 minutes.
Hislop made a stunning block to deny Keane from a corner eight minutes after the break.
Not even that save could compare, however, with Robinson's reaction stop to frustrate Sheringham in the 68th minute.
After a spell of Tottenham dominance, the Hammers took a grip and when Dawson hailed to head clear Matthew Etherington's right-wing corner, Sheringham – who scored 124 goals in 277 appearances for Tottenham, shot at goal from no more than 10 yards.
It looked an equaliser all the way - until Robinson reached up and turned the ball over his crossbar.
Jermaine Jenas could have clinched it for Tottenham in the closing minutes but shot wide after pouncing on a wretched clearance. And that opened the door for Ferdinand's heroic late contribution.
