Jonathan Denver, 24, was pronounced dead at San Francisco General Hospital after he was stabbed at about 11:40 p.m. four blocks from AT&T Park, where 90 minutes earlier the Giants beat the Dodgers 6-4.
Police confirmed that Denver was wearing Dodgers gear when he and another person he was with were attacked. The other man, who was not immediately identified, was bruised after being beaten, according to police.
The two men arrested after the attack were ages 18 and 21, according to San Francisco police. They were not immediately identified.
The stabbing reportedly occurred after a fight broke out when someone made a comment about Dodgers gear, according to KGO-TV.
At least 10 people were involved in the fight, with one man wielding a knife and another a bat, the San Francisco Chronicle reported.
It was not immediately clear if others in the fight were wearing Giants gear, and police declined to comment on a possible motive for the fight.
Detectives were interviewing witnesses as the investigation continues, San Francisco Police Sgt. Danielle Newman said.
The Dodgers and Giants have a rivalry going back generations. In 2011, it turned violent when Giants fan Bryan Stow was severely beaten in the parking lot of Dodger Stadium.