And now the French-born winger is set to appear in Brazil this summer, having been selected for Algeria's 23-man squad by head coach Vahid Halilhodzic, despite having only made his debut on May 31 - two days ago.
Turkish midfielder Muzzy Izzet - who came through the youth ranks at Chelsea alongside John Terry - was the last Foxes player to appear at a World Cup - struggling to break into the squad who finished an impressive third place.
It follows an impressive rise to fame by Mahrez, who was playing for the reserve team of Le Havre less than a year ago. To achieve Premier League football and a World Cup finals appearance in the same year would be any players dream, and with Algeria in a group composed of Belgium, Russia and South Korea, there is a good chance that Mahrez and his countrymen could see the latter stages of the tournament.
Although many see Belgium as definite group winners, Russia, South Korea and Algeria can all be considered as potential runners up - with all three countries coming off the back of impressive qualifying campaigns.
Mahrez is joined in the squad by another plying their trade in the Championship during the 2013/14 season, with Essaid Belkalem - on loan at Watford from Granada - set to appear in the centre of defence for the Greens.
The full 23-man squad is as follows:
Goalkeepers: Mohamed Zemmamouche (USM Alger), Rais Mbolhi (CSKA Sofia, Bulgaria), Cedric Si Mohamed (CS Constantine).
Defenders: Carl Medjani (Valenciennes), Aissa Mandi (Reims), Madjid Bougherra (Lekhwiya), Faouzi Ghoulam (Naples), Rafik Halliche (Academica Coimbra), Essaid Belkalem (Watford), Liassine Cadamuro (Majorque), Djamel Mesbah (Livourne), Mehdi Mostefa (AC Ajaccio).
Midfielders: Sofiane Feghouli (Valence), Saphir Taider (Inter Milan), Medhi Lacen (Getafe), Abdelmoumen Djabou (Club Africain), Yacine Brahimi (Grenade), Hassan Yebda (Udinese), Nabil Bentaleb (Tottenham), Riyad Mahrez (Leicester).
Forwards: Islam Slimani (Sporting Portugal), Hilal Soudani (Dinamo Zagreb), Nabil Ghilas (FC Porto).