A star-studded Barbarians side proved just too strong for Scotland, beating them 40-33 in an open Murrayfield encounter which yielded 11 tries.
Irish fly-half David Humphreys converted five of the Baa-Baas' six tries, while Scotland number eight Allister Hogg was named man of the match for a two-try performance.
Simon Danielli was forced to withdraw from Scotland's starting line-up after suffering a back injury.
Danielli, who was replaced by Stephen Cranston of The Borders, has undergone a scan, but is now a doubt for the summer tour of Australia.
The Scots fielded Bath's uncapped Zimbabwean-born flanker Scott Gray in an unfamiliar back row, with Hogg taking the place of injured number eight Simon Taylor.
The Baa-Baas opened the scoring when scrum-half Mark Robinson wrenched the ball from Chris Cusiter and his over-the-shoulder pass found Fijian winger Vilimoni Delasau, who ran in unchallenged from the halfway line.
The Barbarians' determination to run the ball in their own half almost cost them dear several times but the Scots were unable to profit as fly-half Dan Parks was guilty of missing two simple penalty goals.
Scotland were showing plenty of enterprise, with Simon Webster making some incisive runs on the left wing, but always looked vulnerable to the Barbarians' counter-attacking skills.
They were unpicked by a moment of Brian O'Driscoll magic as a superb pass allowed fellow Irishman Shane Horgan to charge forward before setting up Delasau.
The Fijian was brought down inches from the line but Robinson was on hand to pick the ball up and score.
The Murrayfield crowd finally had something to cheer when Cusiter intercepted a pass and fed Parks, who cut in from the right for a try under the posts.
Hogg then had a chance to score a second with a superb break but was pulled down a few yards from the line.
The Barbarians added a third try as Robinson and full-back Christian Cullen tore Scotland apart on the right to set up Horgan.
And the Irishman made it four two minutes later as he rounded off a sweeping move started by South African number eight Bobby Skinstad.
Scotland pulled themselves back into the game early in the second half as Hogg muscled his way over the line following a break by Allan Jacobsen, who intercepted a pass near the touchline and set up a series of diving moves.
The Scots then almost conceded a farcical try when a lineout down by the Barbarian try line went astray and fell to Italian Aaron Persico.
The Italian set up on a run and fed O'Driscoll, but French veteran Thomas Castaignede lacked the pace to collect the Irishman's intelligent kick forward.
The Barbarians extended their lead when Skinstad set up Cullen for a simple score as Scotland's defence was run ragged.
However the hosts came back with an excellent try by Paterson, the full-back skipping inside two defenders on the left to create just enough space to score.
Two minutes later the gap was closed still further when Parks and Webster combined superbly on the left before feeding Tom Philip. The Edinburgh centre's return pass was fumbled by Webster, but Jacobsen was on hand to collect and drive over the line.
Baa-baas captain Taine Randell restored the advantage, finishing off a neat move, before Hogg burst through a gap to score his second try under the posts.
Scotland poured forward in the final minutes in search of the score which would have brought them level but the Barbarians' defence held firm.
The RBS 6 Nations Championship 2015 was not poised to go down as one of the more "vintage" Championships, though there was great anticipation as the action headed into its final day. What transpired was something that nobody could foresee: "The Greatest Day in Rugby's Greatest Championship."