On September 11, Holt hit a pinch-hit, three-run go-ahead home run off of Ryan Tepera of the Toronto Blue Jays in the seventh inning, giving Boston a lead they would hold onto for a 7–2 win, making them the first team of the year to clinch a postseason berth. Holt finished the campaign with seven home runs and 46 RBIs in 109 games while hitting .277 and playing all infield plus the corner outfield positions during the season. On October 8, Holt became the first player in MLB history to hit for the cycle in the postseason, doing so in a 16–1 rout in Game 3 of the 2018 American League Division Series against the New York Yankees. The Red Sox would go on to win the World Series over the Los Angeles Dodgers, giving Holt his second career championship title.