There have been 31 games in Red Sox history in which a Boston player has hit three home runs. Only five players have done it more than once.
Jim Rice, Mo Vaughn, and Nomar Garciaparra did it twice. Ted Williams did it three times (with two of those games coming in his 16th season at age 38).
Mookie Betts - playing in just his fifth season, who won't turn 26 until October - has done it four times.
(He is the first player in baseball history to have four games with three home runs before the age of 26.