Dzeko soon struck his second to level the scores, before a dramatic late winner from Micah Richards completed an impressive comeback for the Citizens.
Here, Sports Mole looks back at a pulsating seven-goal thriller against the grain of post-season friendlies to see how City edged an enjoyable encounter in front of 46,00 fans at Busch Stadium.
Was the result fair?
On reflection City probably deserved to edge this entertaining affair after controlling possession for long spells, particularly in the first half. Chelsea were clinical and needed few chances to build a commanding lead, but ultimately conceded a string of poor late goals after making a whole host of changes after the interval. There were plenty of positives for both teams and a draw at 3-3 may have been just about right, but Richards put paid to that notion with a burst into the penalty area deep into stoppage time.
The Blues were largely lacklustre in the first 45 minutes but somehow built a two-goal lead, mostly due to the quality of Juan Mata. The Spaniard's cross for Ba's opener was sublime, and his skill to beat Karim Rekik and win a penalty before the break equally impressive. Oscar and Ruben Loftus-Cheek also showed neat touches but Rafael Benitez's side faded late on as replacement goalkeeper Jamal Blackman was beaten four times in just over 20 minutes.
Brian Kidd's team were exciting and creative in attack throughout, but were badly let down by wasteful finishing from David Silva and Sergio Aguero among others. City continued to probe and press in the final third but were punished ruthlessly for a few errors in their own half from inexperienced youngsters. The introduction of James Milner and Dzeko completely changed the match and finally gave the Citizens a cutting edge when it mattered. For sheer effort in a post-season friendly City deserve credit, although some supporters will wonder where that same desire was two months ago.
Sports Mole's man of the match
Carlos Tevez: The Argentine forward deserves this award for sheer persistence in his approach to a largely meaningless match. Tevez chased down every lost cause and was not perturbed when things didn't work out in the final third. Late on his stamina told as he tackled Jon Obi Mikel to create a chance that Dzeko took with ruthless efficiency. On this evidence if motivated incoming City boss Manuel Pellegrini might be well served to keep the temperamental forward next season.
Both sides will now travel to New York as the unlikely battle between interim duo Kidd and Benitez continues on Saturday night at Yankee Stadium. Both sides will be without their England internationals in a match which should give fans a chance to check on the progress of academy stars and fringe players.