The Argentinian came on alongside Jeremy Doku in the second half with City trailing 2-0, and within a minute Erling Haaland had pulled a goal back.
While it might be too quick to say they made that much of an instant impact, the pair helped pinned back the visitors with Alvarez scoring a late winner after an equaliser from Phil Foden.
Dickov says City were far sharper after the break with Alvarez’s positioning making it awkward for the visitors.
“Everything was so much quicker,” he said on Matchday Live’s post-match analysis. “They didn’t give Leipzig a chance to get into their shape when the ball was turned over.
“I thought Alvarez was fantastic when he came on. He played between the lines and it allowed Phil to go and roam a little bit more.
“The centre-half didn’t know whether to come in and then the ball would go down the side to Haaland. He picks up that pocket, slips into Phil, he slips into Haaland and it’s a touch and finish.”
Fellow guest Shaun Goater praised the impact of Doku as he troubled the RB Leipzig defence throughout the second half.
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And the ex-City forward says Pep Guardiola has two exciting options on the left wing with the Belgian a different type of player to Jack Grealish who helps pick apart opponents in a different way.
“He’s just a brilliant winger,” Goater said. “He has patience when he needs it, sometimes he goes direct or changes and the defender thinks he’s done me there. I like how he switches up his game.
“And Jack is a quality player, because he does some really good things for us because what he does is bring the opposition all the way across and gives an advantage on the other side.
“When we move the ball quickly it gives us a two versus one on the other side.”
While it was a tough night for our defence with Guardiola unhappy at the manner of the two goals conceded, Steve Howey praised Josko Gvardiol who was playing against his former club.
The Croatian claimed an assist for Foden’s goal and the former City defender said it was a stylish finish from the midfielder.
“Gvardiol was probably my man of the match, I thought he was excellent,” Howey said. “Even in the first half when we were saying a lot of players weren’t on it, he was.
“He put the ball into Foden and he’s taken the touch and turn, how he manipulates it and is it luck that he puts it through the defender’s legs into the bottom corner? I don’t think it is.
“It’s a great goal and it’s what you’ve come to expect from a top class player like him.”
Dickov has also been impressed with the impact of Gvardiol since his summer move from RB Leipzig.
“He’s got real quality and when he passes the ball he rifles it in,” he added. “Defensively he was great, and with the ball he’s top quality.”
