City cranked up the pressure on their rivals for the trophy with eight wins and one draw in December, leaving them just one point adrift of leaders Arsenal at the end of the year.
Bookmakers have Manuel Pellegrini's men at the head of their title betting and Chelsea boss Jose Mourinho increased the expectations surrounding City by claiming "they know how good they are."
But Wenger believes all the teams in a fiercely contested title battle are capable of claiming the crown in 2014.
"Do you believe him (Mourinho) that City are favourites? Not more than Chelsea, for me, or Man United," said Wenger, whose side were beaten 6-3 at the Etihad Stadium earlier this month.
"They have the squad, yes, they have a squad of names who can pretend to win it, but at the end of the day, it is down to what we do on the pitch.
"Are they, at the moment, completely unbeatable? Not for me.
"They have lost a number of games as well away from home. Man City have played one more game at home, than away. We have played one more game away, than at home, so it is open."
Bacary Sagna is yet to commit his future to Arsenal and could become a free agent in the summer.
But Wenger expects the full-back to take up the offer of a new deal at the Emirates.
"We are not far," said Wenger. "I will push very hard to get it done, yes.
"We cannot stop him from doing that (signing a pre-contract agreement to leave).
"But for me, that is not a problem because when you are a professional football player, you do until the last day, of where you are, your best. If you don't do that, you are not professional for me.
"I don't question Sagna's commitment until the last day of his contract."
Wenger is himself in talks with Arsenal about extending his lengthy managerial spell, but refused to reveal when he will sign a new deal.
"I want to do well for the club and feel that I can help the club to move forward. My commitment is no question for this club," he said.