"A lot of excited people are out, so police have to be a little more vigilant to make sure people aren't partying too much," San Francisco police spokesman Sgt. Troy Dangerfield said.
The Giants beat the Phillies 3-2 this evening, which means they won the National League Championship Series and are headed to the World Series next week.
Drivers honked their cars for at least a half hour near AT&T Park in celebration of the Giants win, causing discomfort to some of the residents in the area.
"People are walking around screaming about the Giants," said Joel Karpiak, a University of California at San Francisco Ph.D. student who lives in the area.
"The street outside my window is like a parade of cars honking," he said.
Several other fans dressed in full Giants paraphernalia have been seen at bars near Mission and 30th streets, screaming and cheering for the team's victory.
"It's great that the city can come together for something," said a fan who identified himself as Tosch. "It's awesome," he said.
Tosch screamed, "Whoo!" along with almost everyone else celebrating the game in the area.
Several people were running near Tosch while firecrackers went off. Others have been seen walking around with a celebratory beer, and about five people banged on drums in the area.
"Tonight, San Francisco is overflowing with Giants pride as this amazing team continues the quest to bring the first-ever World Championship home to San Francisco," Mayor Gavin Newsom said in a statement.
The statement said a Giants flag will remain over City Hall, which will be lit orange along with Coit Tower, the War Memorial Opera House, and the Treasure Island Administration Building in honor of the team's victory.
"As the nation turns its attention to San Francisco and to the World Series next week, the entire city is behind the orange and black," Newsom said.
The Giants will face the Texas Rangers at AT&T Park in the World Series on Wednesday.
"The Giants are gonna beat 'em up," Anto Fly, a Giants fan said.