The Sharks booked their spot in the Super Rugby play-offs thanks to a workmanlike victory over the Jaguares in Durban on Saturday.
A costly defeat for the Rebels against the Highlanders earlier in the day left the door ajar for the South African franchise, who duly took the invitation with a 20-10 win.
Tries from Akker van der Merwe and Kobus van Wyk, coupled with three penalties from Robert du Preez, whose brother Dan was sin-binned in the first half, helped the Sharks to a 17-point cushion by the 53rd minute.
Sebastian Cancelliere's converted score reduced the arrears, but the Jaguares were unable to bring themselves back into the contest.
The Sharks' dubious reward for making the quarter-finals is a tie with the Crusaders, who dominated the regular season.
A 38-12 victory over the Bulls at Ellis Park ensured the Lions finished second behind the Crusaders in the overall standings.
The Waratahs' defeat to the Brumbies allowed the Lions to take advantage and Ruan Combrinck's brace, scores from Malcolm Marx, Courtnall Skosan and Aphiwe Dyantyi, and a penalty try secured a comfortable win and a possible home semi-final.
Swys de Bruin's men will face the Jaguares in the last eight.
