The England international came in for criticism after a poor performance in a 3-1 loss to Bayern Munich in the Champions League at Etihad Stadium on Wednesday night.
Hart was unable to keep a clean sheet in the club’s following fixture as Everton striker Romelu Lukaku opened the scoring before City went on to secure a 3-1 win.
And City vice-captain Zabaleta revealed Hart was bitterly disappointed to concede against the Toffees at The Etihad.
“I think he’s still upset about it,” Zabaleta said. “Joe felt he could have got a stronger hand to it.
“But sometimes it’s really hard for any player when you’re not doing well.”
The Spaniard added the Citizens squad are rallying around their beleaguered goalkeeper, backing Hart to rediscover his best form.
“Most of the lads saw him a bit down in the week,” Zabaleta added. “That’s why it is ¬important as team-mates to support all the players.
“He has to show his strong personality and that he’s coming back to his best. I’m sure he will as he is a great goalkeeper.”
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