Gavin, normally a No 8, found himself packing down at second row to accommodate Dirk Williams, the 35-year-old Australian physiotherapist, drafted in at flanker where the tourists were particularly hard hit by injuries. With 33 minutes gone, the New Zealand-born Williams, a former All Black trialist, carved his niche in Wallaby history by scooping up a loose pass to stroll over in the corner.
Quite what Williams was doing loitering out wide while play raged infield was less clear, but it was undoubtedly a moment to savour especially as the Wallabies were trailing by two Gary Parker penalties and struggling to string passes together in the monsoon.
At least the Wallaby winger Joe Roff proved adaptable enough to use the conditions to advantage by skidding in for a try from 12 metres, his momentum carrying him over the line.
By that stage the tourists were well in command, Tim Wallace having converted a try by Adam Magro and cancelled out Gary Parker's third penalty.
While the Australians appeared content merely to mark time until Saturday's Test at Murrayfield and claim a win without sustaining any more injuries, the Scottish Select looked thoroughly fired up. But the awful conditions meant play frequently became bogged down in a welter of errors although John Steele played tidily at outside-half alongside the eager Derek Patterson.
There was satisfaction, too, for the Scots in the way they blunted the much vaunted Australian driving maul through the efforts of Darren Burns and Ian Elliot along the touchline though it seemed the tourists were content to keep most of their aces up their sleeves.
Scottish Districts Select: Penalties Parker 3. Australia: Tries Williams, Magro, Roff; Conversions Wallace 2; Penalties Wallace 2.
SCOTTISH DISTRICTS SELECT: G Fraser (London Irish); D Officer (Currie), P Rouse (Dundee High), I Wynn (Wakefield), G Parker (Melrose); J Steele (London Scottish), D Patterson (Heriot's); W Anderson (Kirkcaldy), M Scott (Orrell), M Stewart (Northampton), D Burns (Boroughmuir), I Elliot (Hawick), D McIvor (Glenrothes, capt), M Waite (Edinburgh Acads), B Poutney (Northampton). Replacement: S Longstaffe (Dundee High) for Rouse, 70.
AUSTRALIA: S Larkham; B Tune, A Magro (D Campese, 73), R Tombs, J Roff; T Wallace, G Gregan; C Blades, M Caputo, A Heath, J Welborn, T Gavin, D Williams, O Finnigan, T Kefu.
Referee: T Rowlands (Wales).