A passerby who helped save a 10-year-old girl who was being severely beaten by a man in Montreal's east end Pointe-aux-Trembles neighbourhood says he's still in shock, days after interfering in the violent incident.

"The police officers kept telling me that I probably saved the life of this young girl," Dominique Roy told Noovo Info. "I'm very proud of that."

He recalls seeing the 21-year-old suspect walk past him on Tricentennaire Boulevard, near Notre-Dame Street, just seconds before the attack occurred late Monday morning.

The 10-year-old victim, who cannot be identified to protect her privacy under youth protection laws, was walking home for lunch with a friend when the suspect approached her and, according to Montreal police (SPVM), "for reasons still to be determined, started to punch the young girl and drag her a couple of metres."

Roy says he was parking his car when, all of a sudden, two children ran up to him, begging him for help.

"I ran to get him out of there. When I was 10 feet away from him, he saw me. He stopped hitting," he told Noovo Info, adding he called 911. "I grabbed him, too, even though he was hard to control. We kept him on the ground until the police arrived."

Montreal police officers quickly arrived on the scene and arrested the man.

Roy says he propped up the little girl's head, covering her with his coat as they waited for first responders.

Her face was completely bruised.

He says he remembers seeing her lose and regain consciousness at least seven or eight times while she lay in his arms.

"[I] thought she was gone," he admitted, adding she opened her eyes again as paramedics arrived. "She started crying. The police officer asked her age, her name, if she remembered what happened."

The girl was transported to hospital with serious injuries to her head and upper body.

"She's doing better, of course, it'll take some time, she's still in a state of shock," her aunt said at the courthouse Wednesday. "She was a victim, she didn't deserve this."

The suspect, Tanvir Singh, has been charged with aggravated assault, two counts of assault with a weapon causing bodily harm and possession of a weapon for a dangerous purpose.

He has been ordered to undergo a psychiatric evaluation to determine if he is fit to stand trial.

As for Roy, he says he would like to meet the girl once she recovers to give her a hug and remind her that "she's going to have a good life."