Borbón also excelled in the postseason. In four National League Championship Series, he was 1–0 with a 1.26 ERA in 10 games, of which he finished seven. He was especially effective in the 1976 National League Championship Series, pitching 4 scoreless innings of relief in a three-game Reds' sweep. He also pitched well in three World Series, pitching 10 games and going 0–1 with a 3.86 ERA as the Reds were world champions in 1975 and 1976.