The Melbourne outfit have lost the previous five games between the two sides, but on this occasion they converted a 15-10 halfway lead into a 20-point triumph.
The result leaves the Joburg side winless from their first two matches of their four-game Australasian tour following their defeat last week to the Waratahs in Sydney.
The home side outscored the South African visitors by five tries to two, while Emirates Lions struggled somewhat in the lineouts and conceded too many penalties and turnovers.
Andrew Kellaway (2), Richard Hardwick, Isi Naisarani and Ross Haylett-Petty were the try scorers for the Rebels while Jamba Ulengo and Sti Sithole dotted down for the visitors.
Elton Jantjies and his team mates now travel to New Zealand for their next match against the Blues in Auckland.
A stern test awaits the side from Jozi because the Blues followed up their two wins in South Africa with a 24-15 triumph over the Hurricanes Saturday morning (SA time) in Wellington – their fourth away in a row this season.
Rebels 37 (15) – Tries: Andrew Kellaway (2), Richard Hardwick, Isi Naisarani, Ross Haylett-Petty. Conversions: Matt Toomua (3). Penalty goal: Toomua.
Emirates Lions 17 (10) – Tries: Jamba Ulengo, Sti Sithole. Conversions: Elton Jantjies (2). Penalty goal: Jantjies.