Mr Newman is on trial in the Perth District Court accused of causing grievous bodily harm to Brett Marris, then aged 20, in November last year.
Newman made Facebook threats, court told
Giving evidence to the jury on Tuesday, Mr Newman claimed that on the night of the fight, he did not deliberately seek out Mr Marris to exact revenge for sleeping with his girlfriend when they were on a break.
But he had "brushed shoulders" with Mr Marris as he left the Library nightclub in Northbridge.
Newman seeking path back to Eagle acceptance
Supported by teammates, including Nic Naitanui, Josh Kennedy and Sharrod Wellingham, Mr Newman said he had feared for his own safety from the larger Mr Marris, who was with a friend.
"I felt scared because they could turn against me," Mr Newman said.
According to his evidence, Mr Newman was grabbed around the throat by Mr Marris - which is when he hit out to defend himself.
Defence lawyer David Grace QC told the jury it should question the reliability of Mr Marris' evidence, while saying threatening Facebook messages the footballer had sent the victim before the alleged assault were "immature".
Weeks of threats from Mr Newman on Facebook included messages such as: "start digging a grave".
Mr Newman also called Mr Marris a "little girl" and asked why he did not want to meet "for a crack".
In another message, Mr Newman said: "I won't rest til you ey (sic) hurt."
In his closing address, prosecutor Michael Perrella said Mr Newman's claims of self-defence were a "complete red-herring", and questioned why he had not mentioned being grabbed by the throat to the police.
"It is an attempt to portray himself as the victim to take your focus away from the fact that he was the aggressor," Mr Perrella said.
The trial continues.
