Partially-sighted Fachie from Aberdeen and partner MacLean from Grantown-on-Spey were the last of five teams to go and, roared on by a capacity crowd including Hoy himself as well as comedian Billy Connolly, the pair powered to victory in one minute 2.096 seconds.
The reaction from the Glaswegian crowd raised the roof of a venue that has become renowned for its ear-splitting crowds.
As the pair completed their lap of honour around the track, Fachie unfurled a Saltire and held it aloft - seemingly hoisting it in the direction of the man who leant the Velodrome his name, with Hoy clapping his approval from a television gantry.
Wales collected the bronze medal in the same event, with Matthew Ellis and pilot Ieuan Williams coming in almost two seconds after Australia's silver-medal winning duo Kieran Modra and Jason Niblett.
Northern Irish duo James Brown and Dave Readle, the latter combining his duties as a British Cycling psychologist, came in last.
Success for 30-year-old Fachie and 42-year-old MacLean follows the silver medal picked up by fellow Scots Aileen McGlynn and Louise Haston in the women's B tandem sprint on day one.