The courageous Tigers made it four wins in a row the hard way after playing the second half with just two fit men on the bench.
They were out on their feet in the dramatic closing stages of the match, but dug deep to record a famous win - 15.10 (100) to 11.15 (81).
An interchange bungle by Freo with 4:38 remaining saw Jack Riewoldt bang through his fifth goal from point-blank range to put Richmond six points up.
Dustin Martin added the sealer with two minutes left on the clock and Andy Collins put the icing on the cake with the last major of the contest.
Daniel Connors played the game of his career with 35 touches and a goal with Brett Deledio (29 possessions), Chris Newman (26) and Shane Tuck (30) all important.
Riewoldt overcame a sluggish start to finish as the leading goal kicker on the ground with five.
He booted the first goal of the game, but it was to be the Tiger spearhead's only major of a quiet first half.
Damien Hardwick would have been pleased with the early endeavour of his young charges as they took it right up to their top-four opponents. However, their aggression was not always well-directed, with Freo's first three goals coming from free kicks.
Matthew Pavlich was in ominous touch early, switching between the midfield and attack, with two first-quarter goals helping his side to a four-point lead at the first break.
Richmond lived dangerously with a zone defence that worked well for long periods and allowed them plenty of rebound, but also produced defensive mismatches in height and numbers on occasion.
When Freo managed to cause the turnover and get the ball forward quickly, they often found themselves with an extra forward or two.
To their credit, the Tigers still managed to find avenues to goal with Riewoldt well-held, but a fierce clash that saw Angus Graham, Jake King and Ben Nason lying prone on the turf meant they had to hold on grimly as the visitors finished the half strongly.
A groggy and bleeding Nason joined Ben Griffiths, who had sustained a shoulder injury earlier in the term, on the pine for the rest of the match.
Despite a couple of bad misses it was Fremantle by 11 points as the second half got underway, but it was the tenacious Tigers who did all the attacking.
Matt White followed Riewoldt's opportunist goal with a set shot major to snatch back the lead, but his joy quickly turned to dismay as Shane Edwards' errant high-five sent him from the ground bleeding from his left eye.
Riewoldt gave Alex Silvagni the slip to mark and goal midway through the term and that was it for majors for the quarter as Richmond took a surprise seven-point lead into the epic final stanza.
Richmond 5.1 7.4 10.8 15.10 (100)
Fremantle 5.5 8.9 8.13 11.15 (81)
GOALS
Richmond: Riewoldt 5, Collins 2, Connors, Edwards, Griffiths, Webberley, White, Nahas, Martin, Astbury
Fremantle: Pavlich 3, Bradley 3, Hill 2, Morabito, Johnson, McPhee
BEST
Richmond: Riewoldt, Connors, Edwards, Martin, Tuck, Deledio, Newman, Vickery
Fremantle: Mundy, Sandilands, Pavlich, Hill, Bradley, Palmer
INJURIES
Richmond: Tambling out, replaced in selected side by Nahas, Griffiths (shoulder), Nason (facial cut)
Fremantle: TBA
Reports: Jackson (Richmond) reported in the first quarter for rough conduct against Ballantyne (Fremantle)
Umpires: Vozzo, Kamolins, Meredith
Official crowd: 25,707 at Etihad Stadium
The views in this article are those of the author and not necessarily those of the AFL or its clubs