On June 25, 1968 At Candlestick Park – San Francisco Giant rookie Bobby Bonds becomes the second player to hit a grand slam in his first major league game, as Ray Sadecki blanks the Dodgers, 9 – 0. Bonds does it on his third at-bat, facing John Purdin. The only other player to hit a grand slam in his first major league game was Bill Duggleby of the Philadelphia Phillies, who achieved the feat in 1898.

 

Source

Baseball Reference June 25