On September 16, 1973, while playing for the Falcons in a game against the New Orleans Saints, Shiner became the first person to post a perfect passer rating, during what was the first season in which the statistic was officially kept. However, multiple other quarterbacks are recognized retroactively to have accomplished this feat prior to the 1973 season. Shiner completed 13 of 15 pass attempts for 227 yards and 3 touchdowns, with no interceptions in a 62-7 destruction of Atlanta's archrival. The next week in being shut out against the Rams, Shiner would go on to post a lowest possible 0.0 QB rating (unofficially, as he only attempted nine passes).