Zlatan Ibrahimovic's behaviour as he inspired LA Galaxy to a 2-1 MLS win over Real Salt Lake was "unacceptable", according to opposition defender Nedum Onuoha.

Ibrahimovic clashed angrily with Onuoha during Sunday's match and unsubtly goaded the former Manchester City defender after sweeping in his 78th-minute winner.

After the match, Ibrahimovic sought to play down the incident and stated, "what happens on the field stays on the field".

However, Onuoha refused to be bound by that principle and explained he rejected a post-match apology from Ibrahimovic.

The 32-year-old accused the Galaxy's star attraction of threatening him physically and suggested he was not fit to be considered the face of the United States' top-flight competition.

"He came into apologise after the game because from 60 minutes in he's saying he's going to do me, he’s going to hurt me for that game," said Onuoha.

"This is a guy who is the face of MLS, as he calls himself, but this is the way that he plays on the field.

"So, I don’t care. If someone comes in and says that to me, I don't care. I’m not going to accept his apology. It’s unacceptable."

Ibrahimovic said the running battle with Onuoha was responsible for inspiring his decisive performance.

"I like to feel alive," he said. "I like when it becomes duels because sometimes, not that I fall asleep, but I don’t feel alive if they don’t activate me.

"They need to activate me or else it becomes too easy. I know me. When I get angry I feel good."

The goal against Real Salt Lake was Ibrahimovic's eighth in seven MLS appearances this season.