'Horrifying': Girlfriend tells of witnessing alleged attack that left man critical

The girlfriend of a man fighting for life after allegedly being knocked unconscious in Adelaide has told 9News her "heart broke into a million pieces".

Jordan Dodd, 20, remains in a critical condition in hospital with multiple brain bleeds, while his accused attacker faced court today.

Described as a footy-mad, loveable larrikin, Dodd is unconscious after the alleged attack in the city's Hindley Street.

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Dodd was attacked from behind and knocked unconscious just before 5.30am yesterday.

He suffered multiple face fractures, bruised lungs, a lung infection and two brain bleeds.

"Seeing my boyfriend lay there in a hospital bed with tubes down his throat forcing him to breathe with blood everywhere is f---- horrifying," his girlfriend Dakota Leo said

"They had to remove a piece of his skull so they could get it out, then they've put something in his head."

Dakota Leo believes her boyfriend was attacked for protecting her from a group of girls.

"She goes, 'I'll show you what's dog' and grabs me by my hair and rips me and someone smashes me on this side," Leo said.

"Someone smashes me here and I got took to the floor and that's when my boyfriend came running in," Leo said.

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"He was yelling at the girls and then the dude proceeds to run up behind him and jab him in the back of the head,"

Police say 23-year-old Clearview man Craig Weetra was arrested nearby.

He faced court today charged with assault causing serious harm with intent.

His girlfriend and brother were in court too.

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Weetra has applied for home detention.

The prosecution alleged Weetra punched the victim in the head and stomped on his chest before running away.

"My heart broke into a million pieces," Leo said.

"I just hope he gets better."