A man defending his girlfriend from an unwanted advance was stabbed and critically injured this morning during a scuffle inside a trendy Near West Side lounge, police said.

The incident happened at about 12:10 a.m. at the Plush lounge in the 1100 block of West Madison Street, according to police.

Witnesses told police that the 43-year-old victim was quarreling with another man when the second man pulled out a knife and stabbed the victim in the neck, police said, citing early reports.

The victim was taken Stroger Hospital in critical condition, police said. The attacker fled and remained at-large.

The altercation appeared to have started after the attacker began making passes at the victim's girlfriend. The victim stepped in and the heated argument led to the stabbing, police said.

Police hadn't located any surveillance images that captured the stabbing.

Management at Plush -- which operates as a restaurant by day and chic lounge by night -- couldn't be reached for comment this morning.

Harrison Area detectives were investigating.

wlee@tribune.com

Twitter: @MidNoirCowboy