Pep Guardiola's side were handed what looked a straightforward draw and as such they were clipped to 9/2 (5.50) in the outright winner market, but slipped to a shock defeat against Lyon in their opening match.
That 2-1 reverse at the Etihad as Guardiola watched on from the stands has seen the well-fancied frontrunners drift to 5/1 (6.0) in the latest Champions League winner odds.
City became the first English side in Champions League history to lose four consecutive matches in the competition and those poor performances have got to be a concern for their backers.
While the result was a shock, the bookies clearly believe the Citizens will have few problems turning their fortunes around and still make them one of the two likeliest winners.
That's because Barcelona's emphatic 4-0 win over PSV Eindhoven on Tuesday night saw them cut to 5/1 (6.0). Lionel Messi netted a hat-trick at the Camp Nou and is now a best price of 2/1 (3.0) to finish as the competition's top scorer.
Cristiano Ronaldo used to dominate that market, but the 33-year-old saw red in his first European game for Juventus and looks set to miss a return to Manchester United unless his contentious suspension is overturned or shortened.
Bayern Munich are 13/2 (7.50) to repeat their 2013 victory while Liverpool were big market movers after the first round of games. Jurgen Klopp's side got the better of Paris Saint-Germain 3-2 and have been cut from 12/1 (13.0) to 7/1 (8.0).
While Manchester United's 3-0 win over Young Boys was routine, William Hill remain sceptical about Jose Mourinho's side and their long-term credentials in this competition, they're 25/1 (26.0) in the outright winner market.