"We had a great [training] session on Wednesday afternoon and the feeling among the lads is very positive," Zabaleta told the club's official website.
"Sometimes after a game like Southampton you need a few days to think about what went wrong and why, and then come back stronger and I believe that's what will happen.
"I think it was just one of those days when everything went wrong. It's not an excuse, but sometimes when everyone is away for international duty in the days before it is difficult to prepare in the normal way and I think it didn't help us on this occasion."
City welcome Championship club Leeds to the Etihad Stadium on Sunday.