Cora was arguing a called third strike on Red Sox left fielder Andrew Benintendi. The Boston Globe's Pete Abraham showed the pitch was just outside the strike zone:
Benintendi's strikeout came at an important moment in the game. The Red Sox had just scored the second of two runs in the inning and had runners on second and third. Had the pitch been called a ball, Boston would've had the bases loaded with two outs and J.D. Martinez at the plate.
Umpiring has been a minor subplot throughout the 2018 postseason. New York Yankees starting pitcher CC Sabathia called Angel Hernandez "absolutely terrible" after Hernandez was the home-plate umpire during Game 4 of the American League Division Series.