Authorities responded to the fight in the area of 3rd and Perry streets, about six blocks from the stadium, at 11:39 p.m. Police say 24-year-old Jonathan Denver of Fort Bragg was in Dodger apparel when he and the group he was with got into an argument with another group of people, one of whom was wearing a Giants hat.
The two groups traded insults about the Giants-Dodgers rivalry that escalated, and then Denver was stabbed. He was rushed to a local hospital, where he later died.
"While this is one of the most storied rivalries in baseball ... nobody's life should be at stake whether they are at the game, leaving the game or six blocks away," San Francisco Police Chief Greg Suhr said during a press conference.
Michael Montgomery, 21, of Lodi, has been charged with homicide. Police have another suspect in custody and are still looking for two others. A weapon has not been located, police said.
Denver's father, Robert Preece, works for the Dodgers as a security guard.
"I'm devastated. I really hurt for him. He's a great man, great person, and I know Jonathan pretty well as well. Great kid; I can't believe it happened to him," said Preece's neighbor Louie Padilla.
Preece, who has lived in an Alhambra neighborhood for nearly two decades, is well known for his kindness and generosity. He often gives kids in the area tickets to the games.
A life-long Dodgers fan, friends say Preece passed that love on to Jonathan, who visited often and at one time lived with his dad for several months.
The Dodgers released a statement saying the team is "shocked and saddened" about Jonathan Denver's death.
"There is no rational explanation for this senseless act which resulted in Jonathan's death," the Dodgers said in a statement. "The pain that this has caused his family and friends is unimaginable. Words are not enough to describe our sadness. Our thoughts and prayers are with him and his family during this extremely difficult time."
Stadium security and fan behavior came under intense scrutiny after Bryan Stow, a Northern California paramedic, was severely beaten at the Dodger Stadium parking lot following the March 31, 2011, home opener between the two longtime rivals. Stow, a Giants fan, suffered a traumatic brain injury from the attack by two men dressed in Dodgers gear.
"First thing that came to my mind was that maybe they got revenge for what happened in L.A. for Bryan Stow, but it shouldn't come down to that. It's just a game," said Dodgers fan Mauricio Guervara.
The Giants organization said in a statement posted on Twitter, "We were deeply saddened to learn of last night's horrific incident that occurred several blocks from the ballpark. ... While details are still emerging, we want to be clear that there is absolutely no place in our community for this type of senseless violence."
At Thursday night's Dodgers-Giants game, there was a heightened police presence, including undercover officers. A moment of silence was held for Denver.
The Associated Press contributed to this report.