Fraser Hornby is Scotland Under-21s’ all-time top scorer after his hat-trick in a record 7-0 rout of San Marino.
David Turnbull, Barry Maguire, Connor McLennan and Harrison Ashby were also among the goals as Scot Gemmill’s side enhanced their European Championship qualification hopes in Serravalle.
Reims striker Hornby overtook Scott Booth and Jordan Rhodes with his second before making it 10 goals in 17 games.
Victory eclipses a 5-0 win over Finland in 1995 as the U21s’ biggest triumph.
Scotland remain a point behind Group 4 leaders Czech Republic with a game in hand. Victory over Croatia at Tynecastle next month will guarantee a top-two finish and send Gemmill’s team top, before they end the section away to Greece five days later.
The nine group winners and the best runner-up qualify for the finals with the other eight second-placed teams playing off for four places.
Scotland had a new midfield following their victory over the Czechs on Friday, with Ross McCrorie now in Steve Clarke’s senior squad, Allan Campbell suspended and Lewis Ferguson absent from the 19-man squad.
But they immediately took control and Hornby opened the scoring from the penalty spot in the 20th minute before goals from Turnbull and Maguire had the result beyond doubt by half-time.