The encounter in London marked the return of supporters inside the stadium as 8,000 fans gathered to watch the Carabao Cup final.
Aymeric Laporte netted the winner with eight minutes remaining, powering a header beyond Hugo Lloris from Kevin De Bruyne's free-kick.
Mahrez, who was named as the Man of the Match, was a menace to the Tottenham defence all game and was denied a spectacular solo goal in the second half by a fine save from Hugo Lloris.
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The Algerian was delighted to have City fans back in the seats cheering the team on.
"It’s so good to have the fans back," he admitted. "They made a massive difference.
"The atmosphere with just 8,000 fans was amazing and we can’t wait to have more fans back soon."
The winger was also impressed with the patience that the team showed to keep plugging away to eventually get the winner late on.
"We knew it was going to be tough. We stayed focused, we kept dominating the ball and then we scored. I think we deserved to win today.
"You are always scared because it is a good team but we are confident in our game. It is a very good win and we get the trophy again. We are very happy.
"We just focus on every competition that we play in. Today was a final, whether we play well or not we have to win - today I think we played good and won."
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This is City's sixth League Cup success in eight years, meaning we draw level with Liverpool for the most wins in the competition’s history.
The result also means Pep Guardiola becomes the first manager in history to win four in a row (2018-2021).
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