In the final Game 8 (it being a best-of-nine Series), he had a single and scored in the 4-run first inning, and singled and scored again in the second as the Reds cruised to a 10–5 win and their first Series championship. During the 1919 season, his brother Lew Groh appeared in two games for the Philadelphia Athletics. In 1920, Groh slipped slightly to a .298 average, posting solid totals in walks, runs and doubles, and led the NL in double plays for the fifth time with 30. He batted .331 in , but was bothered by injuries throughout the year. He had begun the year with a long contract holdout, only joining the team in June for $10,000 (less than the $12,000 he had requested) on the condition that he would be immediately traded to the Giants. A deal was completed to send him back to New York, where McGraw had long been trying to re-acquire him; but Commissioner Kenesaw Mountain Landis cancelled the trade, requiring that Groh complete the year with the Reds. In December, after the Giants had won the World Series, he was finally sent to New York for two players and cash (varying reports give amounts from $100,000 to $250,000). Although his batting marks were never the same with the Giants as they had been with the Reds, he posted good batting averages with over 20 doubles in each of his three full seasons in New York. In 1922 he led the NL in double plays (25) for the sixth and last time, and also in fielding average (.965) for the third time; in that year he broke Nash's NL record of 220 career double plays. His season highlights came in the World Series against the New York Yankees, as he batted .474 in the five-game sweep (four wins and a tie). Batting second, he was 3-for-3 with a triple in Game 1, singling and scoring in a 3-run eighth-inning rally that propelled the team to a 3–2 win. He singled twice and scored in a 3–0 win in Game 3, and singled and scored again in a 4-run fifth inning in Game 4, with New York hanging on for a 4–3 triumph. In Game 5, he singled with one out in the eighth inning to start a 3-run rally that gave the Giants their final 5–3 lead, although he was thrown out at the plate in the inning.