The City winger broke the deadlock on 27 minutes with a strike worthy of his inclusion in the 30-man Ballon d’Or shortlist, finding the top corner of the visiting net with a sumptuous long-range free-kick.
That strike, Mahrez’s 23rd for the Desert Foxes, set the tone for a deserved victory, with the 30-year-old at the forefront of a convincing performance that helped to maintain top spot in AFCON Group A round two qualification.
Things went from bad to worse for Niger soon after the break, with Youssef Oumarou’s own goal doubling Algeria’s advantage inside 48 minutes.
But the visitors rallied from that setback, and Daniel Sosah halved the deficit just three minutes later to keep their slim prospects of round three qualification alive.
It wasn’t long before Mahrez once again restored that two-goal cushion though, confidently stroking home from the spot just before the hour for his ninth goal in his last ten international appearances.
A fourth followed when Zakaryia Souleymane put into his own net at Stade Mustapha Tchaker, before Islam Slimani rounded off the scoring with a late brace.
Mahrez was substituted soon after the first of those strikes from the former Leicester man, enjoying a well-earned rest ahead of Tuesday’s reverse fixture against Niger in Niamey.
It looks to be a straight shootout between Algeria and Burkina Faso for a spot in the final round of World Cup qualification, with both sides level on seven points from three matches.
However, Mahrez and co. currently hold the advantage thanks to a superior goal difference, helped in no small part by Friday’s convincing win and a thumping 8-0 triumph over Djibouti in their opening Group A match.
Mahrez and the Desert Foxes are back in action on Tuesday 12 October, when they travel to Niamey for a 17:00pm (UK) kick-off.