The Ukrainian side head into Matchday 5 in need of a win and a Dinamo Zagreb defeat to Atalanta to make it through to the knock-out phase.
And with City knowing three points will ensure we head into the draw for the last-16 as group winners, Mahrez believes both sides will play on the front foot.
“It’s a huge game,” he said. “The Champions League is always a high standard and we need to be ready.
“Shakhtar is a big team, a strong team, they are going to try and come here and win because they have to.
“It’ll be an open game and it’s good for us.”
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TICKETS: City v Shakhtar
Mahrez produced another fine display in the 2-1 win over Chelsea on Saturday, scoring a brilliant winner that saw him cut inside past two defenders before curling the ball into the bottom corner.
Having struggled to fully settle in his first season at City, it was the latest in a growing list of impressive performances this term.
Mahrez says he was disappointed with parts of his game, particularly in the first half, but praised the never-say-die attitude of the team.
“I was 50-50,” he said. “First 20 minutes I lost one or two balls I don’t usually lose.
“But slowly I came back into the game, scored the goal and I played good in the second half.
“The team was very good. Sometimes you have to suffer to win and that was the way on Saturday.
“We were happy to get three points.”
