Fulham 1 Leyton Orient 2
First-half strikes from Craig Easton and Joe Keith sent the League Two O's on their way to a brilliant third round victory - and Fulham were never able to come back.
Collins John gave them a lifeline after half-time, but the Dutchman then had a penalty saved by Glyn Garner in a dramatic twist to the tie and Orient held on to book a place in the fourth round.
Less than 10 years ago both these sides were in the bottom division of the Football League, but Orient travelled to Craven Cottage in hope more than expectation against their now glamorous London rivals.
Fulham started with a Luis Boa Morte free-kick fired wide after three minutes, but the visitors showed no fear and attacked their hosts at every opportunity.
Tomasz Radzinski had a goal ruled out for Fulham after eight minutes as he strayed offside, but the first goal of the afternoon came on 17 minutes for the visitors.
Keith's shot was blocked by Cottagers debutant Simon Elliott and Easton hammered in a drive from the edge of the box which deflected over Tony Warner and into the top corner.
On 26 minutes Fulham hit the crossbar through a Sylvain Legwinski cross, and John put a header over the top of Garner's goal 10 minutes later from close range.
On the stroke of half-time Fulham were left stunned as the O's grabbed a second. Easton teed up Keith on the edge of the area and his drive took a deflection off Liam Rosenior and flew into the roof of the net to send the 6,000 travelling fans wild.
Fulham emerged for the second half desperate to ensure they did not become the first Premiership club to be dumped out of the Cup, and put themsleves back in the game on 50 minutes.
Radzinski played a superb throughball to John and the Dutchman hit a brilliant first-time shot into the bottom corner of the net.
The goal gave Fulham hope, but for the next 15 minutes Orient matched them in every area to prove they were not going to lie down and die without a fight.
On 69 minutes the hosts were given the chance to equalise from the penalty spot as Gabriel Zakauni shoved Boa Morte in the penalty area.
John stepped up, but Garner leapt to his left to parry the effort and Easton cleared the danger.
Eight minutes later Zat Knight headed wide for Fulham after a Boa Morte corner, as Coleman's side continued to press on in desperate search of a leveller.
Orient gave every ounce of energy to the cause however, and Fulham were left to hit hopeful long-range efforts - including a Boa Morte strike which flew well wide.
Legwinski's volley was tipped over the bar late on, before the full-time whistle sparked scenes of celebration as Orient enjoyed one of the finest moments in their history.
Man of the Match
Fulham: Collins John
The Dutchman was the only Fulham player who was close to his best, although a missed penalty marred his display.
Leyton Orient: Glyn Garner
The O's shot-stopper did not have much to do, but his penalty save ensured they recorded a memorable victory.