England skipper John Terry was brandished the red card in the second half for two bookable offences, but the Tottenham fans celebrated as if their own side had won the title at White Hart Lane.
The Spurs fans had never seen their side record a win over Chelsea in the Premiership and finally managed to end 16-years of hurt over their west London rivals.
Despite Claude Makelele firing Chelsea into the lead, Tottenham hit back with a header from Michael Dawson and then saw Lennon produce a magical piece of skill for a well-taken second goal to give them a bonfire night to remember.
Tottenham almost made an early breakthrough after just three minutes when Hossam Ghaly burst through unmarked and saw his low shot produce a fine save from Hilario diving low to his right.
However, it was the Premiership champions who broke the deadlock on 14 minutes. Arjen Robben beat the offside trap and raced into the penalty area, but was denied by a superb sliding block by Ledley King.
From the resulting corner the ball fell to Makelele on the edge of the box and he curled in a superb right-foot shot which sailed past Paul Robinson into the bottom right-hand corner.
Robinson then made two fine saves within the space of 60 seconds to keep his side in the game.
The England keeper first denied Michael Ballack's long-range shot and then had to be at his very best again to beat away Frank Lampard's fizzing shot.
And Chelsea were made to pay for those missed opportunities when Dawson brought the home side level on 25 minutes.
Jermaine Jenas planted a sweet free-kick into the penalty box and Dawson rose the highest to flick the ball past Hilario into the corner of the net for his first goal for the club.
Bulgaria international Dimitar Berbatov could have increased Tottenham's lead on the half hour mark when he weaved his way into the penalty area, but saw his low drive turned around the post by Hilario.
After stealing all the headlines for Chelsea in the Champions League against Barcelona , Didier Drogba almost capped off a dream week on 34 minutes when he was picked out in the box by Ricardo Carvalho, but his spectacular over-head kick flew inches past the post.
Robbie Keane got back among the goals for Spurs in their impressive UEFA Cup victory over Club Brugge and should have added to his tally on 38 minutes.
Lennon was causing all kinds of problems for Paulo Ferreira down the left-hand side and crossed in for Keane who found himself completely unmarked in the box, but flashed his header over the bar.
But Keane made up for his miss when he played a major role in helping to set up Tottenham's crucial match-winner on 52 minutes.
The Republic of Ireland skipper raced down the left before crossing in for Lennon whose first touch took him past Cole and he made no mistake striking the ball into the corner of the net.
The game erupted into controversy on 74 minutes when Terry was shown the red card by referee Graham Poll.
Terry was involved in an off-the-ball incident with King which sparked a melee between both sets of players, before Terry was shown his second yellow card of the game.
Despite being reduced to ten-men, Chelsea had three golden opportunities to snatch a late equaliser.
Substitute Salomon Kalou saw his curling shot beaten away by Robinson on 80 minutes, while Lampard looked certain to get his name on the scoresheet four minutes later, but his shot was blocked superbly by King.
Mourinho must have known it was not going to be his day when Robben saw his curling shot cannon back off the post three minutes from time.