Manchester City repeated their victory over Saint Germain, after they beat them 2-1 in France.
Mahrez scored the first goal with a shot in the 11th minute with his right foot, and added the second goal with his left foot in the 63rd minute.
The first leg, which was held at the Princes Park in France, ended with City winning, with two goals.
The most remarkable achievement in City’s history was qualifying for the semi-finals in the 2015-2016 season before the defeat by Real Madrid.
The ancient English team (141) wrote its coach Pep Guardiolas first appearance in the most prestigious and most expensive European Championship final since 2011, when he led Barcelona to win two titles in 2009 and 2011.
Riyad Mahrez became the first Arab player to score at least a goal in the first-leg semi-final of the Champions League since the start of the competition in its history in 1955.
City is waiting for the winner of the other semi-final between Real Madrid and Chelsea, at Istanbul’s Ataturk Olympic Stadium, on May 29.
The match began with a caution from the two teams, and Ederson sent a long pass to Zinchenko, who passed it to Kevin de Bruyne, who fired to bounce the ball from the Saint-Germain defense, and did not wait for Riyad Mahrez, so he shot it with his right into the net in the 11th minute.
Marquinhos almost equalized from a powerful header, but his shot hit the crossbar. Then Angel Di Maria snatched the ball from Bernardo Silva and hit his left side next to the post.
In the second half, from a counterattack, Neymar relied on himself instead of passing, and tried to dodge the defense, but Zinchenko intervened and dispersed the ball.
From a quick counterattack, De Bruyne passed to Phil Foden, sending a crawling cross, which Mahrez met with his left foot into the net.