Don't try to call me out, maggot: Raging Barton's tirade at former City team-mate Hamann
, and his family life.
Hamann began gambling after his marriage broke down towards the end of his footballing career.
When it all kicked off: Hamann told Barton to keep out of club politics
Old team-mates: Hamann left and Barton (centre) playing for Man City
'There was a time when I was on my own
when I got into spread betting. A painful and expensive experience,'
Hamann told BBC Radio Manchester last year.
'You have to look in the mirror and say “Can you carry on like this or this is way you want to carry on”'
He added: 'There was one night which cost me over 200,000 and that was obviously a long and painful night.
To and fro: The argument got personal with Barton persisting on his tangent
Blue boy: Hamann with Stuart Pearce when he signed for Man City
'You've got face up to it and when you wake up the next morning you look in the mirror and don't like what you see.'
The Twitter row continued with Barton seemingly becoming increasingly angry as the jibes he sent to Hamann became more personal.
'What a player you where (sic)' typed Barton. 'Tragic. Now do one Tourette's face!'
Using the term 'England international', with reference to Barton's international career which has seen him win just one cap, Hamann antagonised his target.
In a bizarre conclusion to the conversation, Barton tweeted: 'Disappointed in myself for getting involved in that. But never let a dog try to tell u its not a dog an that u are! A dogs a f****** dog…'.
The pair had played alongside each other in City's central midfield in the 2006-07 season.
Barton then moved to Newcastle at the end of that year, a club Hamann had played at almost a decade earlier.
Former Newcastle player Nolberto Solano then chipped in, telling Barton he was a 'good player but lack(ed a) yard of pace. Also lost temper too much.'
He also had kind words for Hamann, saying the man who had won the Champions League and played for Germany over 50 times deserved respect.