McNally was selected to the All-Star Game for the first time in 1969, finishing the season with 20 wins. He threw 11 shutout innings to beat the Minnesota Twins in Game 2 of the first AL Championship Series, then faced the New York Mets twice in the World Series. He hit a home run against Jerry Koosman in one of the games, but the Orioles were defeated in five games. In 1970, McNally tied for the AL lead with 24 wins. He hit a grand slam in Game 3 of the World Series against the Cincinnati Reds, becoming a World Series victor for the second time as the Orioles won the World Series in five games. He missed six weeks with an injury in 1971 but still pitched enough to be one of four Orioles to win 20 games that season. McNally beat the Pittsburgh Pirates in Game 1 of the World Series, lost Game 5, and won Game 6 in relief, but the Orioles were defeated in seven games.