Kaijie Yang sentenced after assault at New Yen Yen supermarket in Chatswood

A store worker was left unconscious after two staff members came to blows at a northern Sydney supermarket. See what triggered the brutal attack.

Kaijie Yang was sentenced at Horsnby Court after the assault at New Yen Yen store in Chatswood.

A man “forcefully” mopping into a co-workers ankles was enough to trigger a brutal assault which left a 61-year-old unconscious and shoppers stunned.

Kaijie Yang, 37, pleaded guilty to common assault and faced Hornsby Local Court on Wednesday.

Police facts state the two co-workers at New Yen Yen supermarket at Chatswood erupted into argument after Yang accused the 61-year-old victim of “substandard” work.

Days later, Yang was stacking shelves when the victim mopped his ankles “with force” – leading Yang to punch the victim to his face, according to police facts.

The pair then wrestled – as caught on CCTV – before Yang punched the victim “several times” to the back of the head while standing over the man.

The victim lost consciousness from the assault, according to police.

New Yen Yen supermarket in Chatswood

The ambulance arrived and performed CPR, as the victim continued to fall in and out of consciousness.

Yang told police the victim had instigated the assault – and informed police that the older man was armed with a small knife.

The victim claimed he had blacked out and couldn’t remember what happened after the mop touched his ankle.

Police facts state there was a case for Yang acting in self defence, however claim the continuation of the assault – to a point at which the victim was knocked out – was deemed “well above self defence”.

Police noted the age disparity was an aggravating factor.

The victim was found with a protracted box cutter knife attached to his mop but police facts state that “at no stage were they in his hands”.

The victim “forcefully” mopping into Yang’s ankles was enough to trigger the brutal assault.

Court documents reveal the pair had known each other for two months but had never spoken.

The victim was also charged with common assault and will face the same court on July 26.

Defence lawyer, Mr Liew, said Yang was remorseful and had never come before a court.

Magistrate Alexander Mijovich said he “did not accept” that Yang had acted in self-defence.

“You could’ve walked away. To suggest that someone mopping a floor requires a punch to the back of the head as self defence is not a matter for a non-conviction,” Mr Mijovich said.

Mr Mijovich said he put weight on the fact Yang had no other matters on his record – but condemned the act.

“Being on top of a 61-year-old is unacceptable behaviour – it doesn‘t matter if he mopped your ankles.”

Yang was convicted and fined $1000.