On May 2, 2018 — Mookie Betts hits three solo homers to lead the Red Sox to a 5 – 4 win over the Royals. All three blasts come off Danny Duffy, with the last one breaking a 4 – 4 tie in the 7th. It is already the second three-homer game for Betts this season and the fourth of his career, tying him for the franchise record held by Ted Williams. At 26, he is the youngest player to have four such games.

Source:
Baseball Reference May 2