In game one of the 1980 American League Championship Series against the Royals, Underwood pitched what should have been a 1-2-3 eighth inning. Instead, Yankees first baseman Bob Watson made a two out error. This opened the door to the Royals scoring two more runs in their 7-2 game one victory. Underwood pitched again in game three; the Yankees were down 2-0 in the series, and 4-2 in game three when Underwood was handed the ball. Underwood pitched two scoreless innings, but so did Royals closer Dan Quisenberry, to complete the three game sweep.