The death of Brian O'Donnell was the third homicide to be recorded in the city over the Canada Day long weekend.
Officers were called to the 300 block of Langside at about 5:30 a.m. Sunday to check on the well-being of a person.
O'Donnell was found at the scene with life-threatening injuries. He was taken to hospital, where he later died.
Investigators have determined that O'Donnell was confronted near his home and stabbed, but police say the exact cause of death has yet to be confirmed by an autopsy.
"A very unfortunate incident, but again, investigators are still working very hard behind the scenes and trying to determine exactly what took place," Const. Jason Michalyshen told CBC News on Monday.
Michalyshen said it appears O'Donnell and the woman who was arrested were unknown to each other.
The woman has been charged with second-degree murder in connection with the incident. She is in custody.
Police were at the scene throughout Sunday and Monday morning. Officers were seen taping off the area around a rooming house on Langside.
Rachel Carrier, who lives in the home, said she was surprised by the news and had not heard any details about what happened.
"It's very quiet. No one bothers no one. We say good morning or 'How's the cat?' Yeah, very friendly people," she said.
3 homicides in 2 days unusual: police
Two other men died in separate stabbing incidents on Saturday.
Michalyshen acknowledged that it's not common for officers to be responding to so many homicides in one weekend.
"I think it's safe to say that it is uncommon that we're acknowledging three homicides," he said.
"It's very, very unfortunate but again, the men and women of the Winnipeg Police Service go out there day in and day out and do what they have to do."
The latest cases bring the total number of homicides in Winnipeg so far this year to 13.
At this time last year, there were 18 homicides in the city, Michalyshen said.
On Sunday, Const. Eric Hofley said investigating three homicides within such a short period is not only unusual, but it also puts a strain on police resources.
"It is a drain on resources," he said.
"Of course our members, when the need arises, are always able to rise to the occasion. What it does do, though, is take so many resources that those calls — and often serious calls — that are waiting for dispatch can't be gotten to in a timely manner."
Michael James Flett, 30, died in an apparent stabbing Saturday in the 400 block of Manitoba Avenue.
Officers found Flett suffering from stab wounds at about 4:30 a.m. He was taken to hospital with life-threatening injuries, but he later died.
Investigators are asking anyone with information about the case to contact them.
Victim a 'gentle young man,' says aunt
Also on Saturday, John James Allen Lund, 25, was killed following a separate stabbing at a home in the 400 block of Pritchard Avenue.
Police said a fight started inside a house party with several other men. The altercation escalated and Lund and another man were assaulted.
Officers were called to the home at around 2:15 a.m. and both victims were taken to hospital in critical condition.
Lund later died, while the other man was upgraded to stable condition.
Amanda Lund said her nephew — known as "John John" — was a good person who loved his family.
"He was very caring and loving and [a] gentle young man," she said Sunday.
"It hurts me. I don't understand why people have to hurt other people just to get a thrill in life. It's not normal."
A 22-year-old suspect who was at the house party has been charged with second-degree murder and attempted murder.
Police are not ruling out gang connections as a factor in the incident.Suggest a correction