"I came up just to be here," Castillo said. "Win or lose, there was no way I could miss this."
Despite being born and raised in Los Angeles, Castillo became a Giants fan in 1989, and his loyalty to the team has remained since.
A short walk down the concourse, a pair of friends born well after the 1989 season ate hot dogs. Andrew Acevedo and Matt Genardini, both 15, came to the park after their school day ended in Redwood City.
"I'm one of the only ones at school who wears a lot of Giants stuff," Genardini said of his classmates. "I'm definitely the biggest Giants fan in my family."
Acevedo is a Yankees fan but watched the clinching game of the 2012 World Series at City Hall in San Francisco and came to support his friend's Giants on Wednesday.
Shortly before first pitch, Lou Seal, the Giants' mascot, and Renel Brooks-Moon, the ballpark's public-address announcer, made an appearance on the field. After a video showcasing the team's regular-season highlights played on the videoboard, Brooks-Moon led the crowd in the team's famed "Yes, yes, yes" home run celebration.
The loudest cheers came after the crowd was asked if it would like to see another home game inside of the ballpark this season.
Ryan Hood is an associate reporter for MLB.com. Follow him on Twitter @ryanhood19. This story was not subject to the approval of Major League Baseball or its clubs.