In , Fleming and Kapp led the Lions to a 12–4 record and the CFL Western Division championship. The Lions next faced the Hamilton Tiger-Cats in the 1963 CFL Championship Grey Cup. During the 1963 Grey Cup game, Fleming was involved in a widely discussed and controversial play as he was hit by Ti-Cat defensive lineman Angelo Mosca, while Fleming was out of bounds, resulting in Fleming's absence from the remainder of the game (and a trip to the hospital). Despite a disappointing end to the season (the Lions lost to the Tiger-Cats, 21-10), Fleming had his finest season as a professional football player, as he rushed for 1,234 yards on 127 carries for an incredible 9.7 yard average.