On April 22, 1876, the Boston Red Caps beat the Philadelphia
Athletics, 6-5, in the first official National League baseball game. 

The game, which lasted a little more than two hours, was played
in "favorable" weather before 3,000 fans. "Great interest was
manifested in the result," the Philadelphia Inquirer reported,
"as it really was the first game of importance played this season."

"The Athletics should have won the game," the newspaper added,
"but their fielding was poor." Betting on the game was "about
even.”