The Liverpool star netted a stunning second-half effort from the edge of the box to cancel out Erling Haaland's first-half opener.
League-leaders City were dominant for large periods as Alexander-Arnold struggled to cope with Jeremy Doku in the opening 45 minutes.
Speaking on commentary, legendary England full-back Stuart Pearce said: "The body language of Trent... he's on the backfoot.
"He's saying, 'Come and take me on. I'm nervous as a kitten.'"
But Alexander-Arnold would silence his doubters in the second-half, getting to grips with Doku and earning a precious point for the Reds.
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He celebrated the superb 80th-minute strike by putting a finger to his lips a shushing the Etihad crowd.
Speaking afterwards, Alexander-Arnold said: "To come here and get a point is a good result - we needed it.
"It instils the belief that even when we don't play well against the champions who won the treble then you are doing something right. We dug in deep today."
He added: "It's always good to celebrate in front of the fans, you get to see different faces. It's funny!"
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