Only four players have had three-homer games in World Series competition -- Babe Ruth (who did it twice), Reggie Jackson, Albert Pujols and Pablo Sandoval.
Probably the World Series. If you mean a single event, probably the All Star game, or the first game of the World Series.
Five players have hit three home runs in a single postseason game. Babe Ruth and Reggie Jackson did it in the World Series. Three players accomplished the feat in a League Championship Series: Bob Robertson of the Pittsburgh Pirates in 1971; George Brett of the Kansas City Royals in 1978; and Adam Kennedy of the Anaheim Angels in 2002.
Reggie Jackson hit three home runs in Game 6 of the 1977 World Series. He also hit five overall homers in that Series.
SS Roy Hughes, a single, in the 9th inning of Game 7 of the 1945 World Series.
The three outstanding players of the 1947 World Series in New York City were Cookie Lavagetto and Al Gionfriddo of the Dodgers and pitcher Bill Bevens of the Yankees.
The weather did not affect any World Series games in 1994. On August 12 the players went on strike which caused the league to cancel the World Series.
In the 1990 World Series, Cincinnati Reds outfielder Billy Hatcher tied New York Yankees catcher Thurman Munson's record of seven consecutive hits over the first two Series games. Munson's pulled off the feat in the 1976 World Series.
2 ... 1997 Florida Marlins and 2010 San Francisco Giants.
He hit 3 home runs in a single World Series game. He joined Babe Ruth and Reggie Jackson in that elite group of hitters to do so.