The Amsterdam giants were hoping for more after going two goals up early on, and the former Netherlands international believes his team missed a chance to deal City a huge blow
Siem de Jong netted twice in the opening 20 minutes to gift the Dutch side a 2-0 lead, but Yaya Toure pegged one back for the Citizens before the break, with Sergio Aguero eventually restoring parity after the interval, much to the dismay of the Eredivisie champions.
"Before the match started, we would have taken a 2-2 draw here. But after the match I have the feeling that the players were actually disappointed with the result," De Boer stated at a press conference.
"We could have delivered a hammer knockout blow to City. It is a good sign that the players were disappointed with this result. We could have taken a giant step tonight.
"That they scored their second goal out of nothing was very disappointing for us. But you know when you play here, it will get tough."
Ajax take on Borussia Dortmund in their next Champions League match, and De Boer has not given up hopes of making it to the knockout stages just yet.
"We aim to stay in the Champions League, and although Dortmund are very strong, we proved over there that we are capable of playing good football."
Ajax sit third in Group D, trailing leaders Borussia Dortmund by four points with two games to go.