Premier League leaders Manchester City coasted past Championship pace-setters Fulham with a 4-1 win in the FA Cup fourth round.
Manchester City were stunned as Fabio Carvalho opened the scoring after just four minutes on a drizzly afternoon at the Etihad Stadium but soon levelled through Ilkay Gundogan.
John Stones then headed the hosts ahead as the frantic start continued and Mahrez put the result beyond doubt with two efforts – the first from the penalty spot – early in the second half.
It made for a sweet return to club action for Mahrez after a difficult month away at the Africa Cup of Nations, where Algeria suffered a surprise early elimination.
Mahrez missed a crucial penalty in a decisive match against Ivory Coast but he had no qualms about stepping up to the spot on this occasion.
The Citizens will also be happy with the workout after their recent winter break but they were caught out early on in a lively opening that saw three goals inside the first 13 minutes.
Carvalho was the first to register, the collapse of his proposed deadline-day move to Liverpool clearly having not affected him.
His well-crafted opener was created by a former Liverpool player, Harry Wilson, who got behind the defence and swept a fine ball into the box. The in-rushing Carvalho simply turned the ball past City’s second-choice keeper Zack Steffen with a fine first touch.
Not surprisingly, Manchester City were quick to respond and it took them just two minutes to equalise.
Jack Grealish had a shot blocked but Joao Cancelo picked up possession and found Mahrez, who in turn picked out Gundogan for the German to finish.
Oh, he's back alright! 💪
— Manchester City (@ManCity) February 5, 2022
City claimed the lead after winning a corner just seven minutes later. Stones went forward and timed a run superbly to meet Kevin De Bruyne’s inswinging cross and beat Paulo Gazzaniga with a strong header.
The pace dropped after that frenetic start but Fulham were in no mood to lie down and attacked back with Carvalho remaining busy and Wilson almost picking out Aleksandar Mitrovic with a cross.
City went close again after Fernandinho clipped the ball into the box and Grealish and Gundogan combined but the German shot over. Grealish also released Mahrez after a good break but Fulham got back to clear and then had a chance when Mitrovic missed the target.
City stepped up the tempo after the break and soon killed off the contest.
Grealish began to run at the defence more and was tripped by Joe Bryan after one mazy dribble into the box.
Referee Jarred Gillett pointed to the spot and Mahrez stepped up to fire home, undoubtedly making himself feel better after his recent miss in Cameroon.
Mahrez was not finished there either and he claimed a second just four minutes later after De Bruyne broke from the halfway line and picked him out with a fine low ball. His strike was not the cleanest and took a slight deflection but it still had too much for the exposed Gazzaniga.
City then lost impetus as manager Pep Guardiola made all five available substitutions but the hosts remained in full control.
Substitute Rory Delap thought he had headed a fifth in the last minute but the offside flag was raised.