How they did it:

Two missed calls by the umpires impacted Game 6. In the fourth inning of the scoreless game, the Royals' Frank White was called out on an attempted steal of second base, but replays show he had beaten the tag. The following batter, Pat Sheridan, hit a single to right field. With this single, White may have scored the go-ahead run, though it is uncertain whether the assortment of pitches thrown would have been similar with a runner on base.

Then in the ninth inning with St. Louis leading 1–0, Jorge Orta led off the bottom of the ninth with a ground ball to Cardinal first baseman Jack Clark, who flipped the ball to Cardinal pitcher Todd Worrell covering first. First base umpire Don Denkinger called Orta safe, but television replays later showed that Worrell had beaten him to the base. Steve Balboni followed with a single to left, moving Orta to second base. Jim Sundberg's sacrifice bunt, instead of moving up the runners, ended up in a force out at third. With Hal McRae batting next, Cardinals' catcher Darrell Porter, who had played four seasons with the Royals, allowed a passed ball, and both Kansas City runners moved up. McRae was intentionally walked to load the bases. Dane Iorg would then pinch hit for Dan Quisenberry, and his single to right field drove in two runs giving Kansas City a 2–1 win. The next day, October 27th, Game 7 ended in a 11-0 win.