The Citizens hit the ground running, with David Silva opening the scoring only a minute into the encounter off Kevin De Bruyne’s assist.
Sergio Aguero doubled the lead six minutes later from the penalty spot before Algeria international Mahrez found the net in the 12th minute, with a deflected free-kick to further compound the woes of their visitors.
Bernardo Silva scored the fourth goal for City before Nicolas Otamendi made it five before the half-time break.
City continued their imperious performance after the restart, with Portugal international Silva grabbing his second and third goals in the game before De Bruyne sealed the commanding display off a Mahrez assist.
Mahrez will hope to make his fifth start when Manchester City take on Preston North End in a League Cup outing on Tuesday.