A cell phone video showing a New Year's brawl that led to a young man's death was played in a downtown Toronto courtroom Wednesday.

Court heard the video was submitted anonymously to police in 2012, after 24-year-old Mike Pimentel was stabbed to death in Liberty Village.

Shawn Poirier was arrested in Calgary nearly four years after the homicide. He has pleaded not guilty to one count of second-degree murder.

The Crown's star witness, Sascha Harten, told court she and her then-boyfriend Poirier arrived in Toronto from Moncton, New Brunswick to celebrate New Year's Eve on Dec. 31, 2011. The two had spent much of the day with Poirier's cousin, shopping, eating and drinking.

By the early morning hours of Jan. 1, 2012, Poirier and Harten had parted ways with Poirier's cousin and were walking alone through Liberty Village. Harten rated their level of intoxication as "seven" on a scale of one to 10, with one being sober and 10 being extremely intoxicated.

Unable to find a washroom, Harten said she opted to urinate behind a planter while Poirier blocked her from view with his jacket.

"Someone was yelling from across the street," Harten said. "He was angry that I was urinating outside."

In her opening address to the jury on Monday, Crown attorney Sarah De Filippis said the "someone" Harten referred to was Pimentel.

A yelling match ensued between Harten, Poirier and Pimentel, Harten said.

"He came toward me and I told him to f**k off. He grabbed me and threw me across the street," she said.

The cell phone video shows Pimentel throwing Harten to the ground.

"They were just trying to get at each other, standing up. Shawn was trying to get away and the guy was grabbing his jacket, trying to pull him closer," Harten said.

During the video, Pimentel is heard saying, "Come on tough guy, come on tough guy. You're a f**kin' tough guy, right? You're a tough guy, right?" A spectator is then heard saying off camera, "Just walk away."

The video ends with both men still on their feet.

Harten testified that about 30 seconds after the video ended, the men were on the ground, "jabbing" at each other.

At some point, Harten said, she heard someone say the word "knife," though she testified she did not see a knife.

Seconds later, both men were on their feet, running in different directions.

"Mike was able to walk for a few blocks after the fight before collapsing in the street," De Filippis said. "An ambulance was called and he was taken to the hospital. Despite medical treatments, however, he died from injuries caused by nine stab wounds which had been inflicted on his body."

Pimentel's friend Christopher Ferreira testified Tuesday that Pimentel had become separated from their group of friends after ringing in the New Year at Liberty Grand. The plan was to meet back at their mutual friend's condo in the area.

Following the fight, Harten testified that she hailed a cab, but, "I was told to get out of the cab because I was full of blood," having had her hand "slashed" at some point during the altercation.

She called Poirier from another cab, she said.

"He thought that he had murdered someone and he told me he got rid of his hat and his knife," Harten said, later clarifying that Poirier had used the word "killed" and not "murdered."

"He told me that he discarded his hat and his knife because his hat was full of blood."

A bloody folding Buck Knife — the type Harten testified Poirier carried — was found days later in a planter box near the scene.

Under cross-examination by defence lawyer Magda Wyszomierska, Harten testified that after telling Pimentel to "f**k off," she and Poirier began walking away.

Wyszomierska repeatedly referred to Pimentel as "the angry man" in her questioning of Harten.

"Do you recall telling the man to stop?" Wyszomierska asked.

"Yes," Harten replied.

"And you meant stop attacking Shawn," the defence lawyer said.

"Yes," Harten replied.

"And does he?"

"No."

Harten testified she believed Pimentel was high on drugs at the time. She later told police she believed Poirier was acting in self-defense.

The trial continues Thursday.