Joe Hart makes Ange Postecoglou 'constant losses' Tottenham claim
The former Hoops boss is under pressure at Spurs, having lost 16 of 30 Premier League matches this season.
The London club are on course to finish outside the top 10 for the first time since 2008.
Speaking on TNT Sports’ YouTube channel, Hart discussed the current situation at Tottenham and how it's impacting Postecoglou's demeanour in post-match interviews.
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The 37-year-old said: "I loved him, but I was in a successful team, playing, you know, some football that I'd never played in my career."
When asked if the Ange he sees now is different from the one he played under, Hart said: "To an extent, but he was always engaging in terms of, he'd answer the question, but he'd answer it his way.
"Even him having a conversation with a fan about being respectful, that's kind of who he is.
"But just the Tottenham team, the constant losses, it's bringing that side out of him more."
Hart went on to explain that Postecoglou's confrontational side was present at Celtic, but the constant losses at Tottenham are making it more prominent.
He said: "But it was there when we were at Celtic.
"If we lost the odd game or we were questioned about the way he played, especially in Europe.
"We went to Real Madrid and went toe-to-toe with them.
"We did all right at home, but we got pumped five-nil away.
"But he stood by it and he would stand by anyone who called him out.
"Twenty-man press conference, if one man was whispering about him over there, he'd be like, what you saying?
"What have you got to say?
"Say it to me.
"But at Tottenham it's difficult because he's constantly having to deal with it."
Hart played two successful seasons under Postecoglou before the 59-year-old moved to Tottenham Hotspur.