The Premier League champions came from a two-goal deficit to draw 2-2 with Ajax at the Etihad Stadium last night but a controversial offside goal by Sergio Aguero and a denied penalty on Mario Balotelli has "frustrated" the team.
"I didn't see the penalty and haven't see it on TV but I saw the Aguero goal that was given offside," the Manchester Evening News quotes Zabaleta as saying. "It was onside and that's why we are disappointed. It was really important to win, especially as Real Madrid and Borussia Dortmund drew.
"We knew it was not offside, and on the penalty we were frustrated by the decision. We were frustrated and disappointed by the referee's decisions, but in the end you can do nothing."