Richmond were below full strength and the form that made them early tips for the title, but they still possessed a sharp enough edge in the backs to take the points with a second-half flurry of tries. Scottish began the match as they have spent much of the season - on the back foot - but the defensive skills they have had plenty of chances to hone enabled them to reach the break with their line intact while the boot of Jannie de Beer guided them to a 9-6 lead at the other end of the pitch.
Despite the former Springbok serving early warning of his threat with the dead ball when he rattled the crossbar from 40 yards, Richmond persisted in presenting him with scoring chances. A Scottish line-out on the visitors' goal line yielded a penalty that provided de Beer's first points midway through the first-half before he landed a second effort from the 10m line.
Respite, however, was not far away for Richmond, although when it came it was provided by de Beer himself rather than their own efforts, the fly-half being sin-binned for a clothes-line tackle on Nick Walne after 25 minutes.
Earl Va'a halved the deficit with the resulting penalty but his team could not capitalise on de Beer's absence. In fact, the South African's return saw Richmond fall further behind as he stepped straight back to kick a third penalty after aggressive tackling from the Exiles turned over possession in front of the posts.
Va'a replied in kind soon after and levelled the scores early in the second-half with his third penalty. That blow prefaced a bruising spell of stalemate eventually ended by two Richmond tries in five minutes.
The first was a gift, Adam Vander charging down Iain McAusland's attempted clearance and collecting the rebound to stroll over on the right. The second was an altogether sharper effort as Richmond moved the ball flat across the Scottish posts for Va'a to diagonal back inside and shimmy over for a try he improved himself. Despite the 12-point deficit, though, Scottish refused to buckle and pulled themselves back to within a score after mounting a sustained battering on the Richmond door. The Exiles' powerful pack created the platform deep in the visitors' 22 for scrum- half Guy Easterby to wriggle over from close range.
Richmond were destined to have the final word, as Vander burst from a driving maul to surprise the Scottish defence and go over from 20 yards to seal only his team's second away win in their last five attempts.
London Scottish: I McAusland (R Smith, 65); K Milligan, J Bonney, R Eriksson (R Davies, 49-55), S Forrest; J de Beer, G Easterby; P Johnstone, D Rudham (D Cummins, 65), P Burnell, E Jones (M McAtamney, 65), M Watson, S Fenn, R Hunter (G Manson-Bishop, 65), S Holmes (capt).
Richmond: M Pini; N Walne, A Bateman, M Dixon, S Brown; E Va'a, A Pichot (capt); D McFarland, D Williams (A Cuthbert, 77), J Davies, B Cusack, C Gillies, R Hutton (M Swift, 77), L Cabannes, A Vander.
Referee: S Piercy (Yorkshire).