The 22-year-old confronted two men after seeing them allegedly set upon another man in Lydiard St Nth, near Police Lane, about 2.30am.

One of the men allegedly produced a 10-12cm knife and thrust it into the victim's stomach.

``It was ... just some university students having a night out and someone's decided they'd borrow some money off him without asking, and it just turned nasty from there,'' Detective Senior Constable Jeff Highthorn, of Ballarat's Criminal Investigation Unit said.

A 20-year-old Ballarat man was charged late last night over the the stabbing after surrendering himself to police at about 8pm.

He appeared before a bail justice at an out-of-sessions court hearing, charged with intentionally causing serious injury and was remanded to appear in Ballarat Magistrates Court today.

Two co-accused, a 20-year-old man and 21-year-old woman, were charged with assault and remanded in custody to front court today.

Police allege the drama unfolded when a Ballarat man, 20, was eating a tray of chips in Police Lane and a woman stole his wallet.

The university student chased the woman but was confronted by two of her male friends in Lydiard St.

Det Sen Const Highthorn said one of the men allegedly pushed the student to the ground, while the other punched him in the head and kneed him in the chest as he tried get up.

A group of onlookers, including the Batesford man, went to the victim's aid.

It was at this time that one of the attackers turned on the Batesford man, pulling out a pocket knife and stabbing him.

The victim was taken to Ballarat Health Services Base Hospital with a 2-3cm stab wound and remained in a stable condition yesterday.

Harley Cannard, 20, of Newington, and Shannon Jeffrey, 21, of Ballarat East, appeared in Ballarat Magistrates Court late yesterday.

Cannard faces one count each of intentionally causing injury, theft and assault in company, while Jeffrey has been charged with theft, assault in company and unlawful assault.

The pair were remanded in custody and are expected to apply for bail this morning.

Another man, Trent Bunney, 18, of Ballarat, also appeared in court charged with driving offences. Police allege he was driving the accused around while disqualified.