In years when Mario was hurt and didn't play many games. Mario was clearly better wants they played with equal players. Gretzky had the better career but it isn't much of an argument who was the better player in his prime. A healthy Mario in his prime was better than Gretzky. Look at that 199 point season when Mario played on a line with Rob Brown who was a career minor league player in his prime years after the league realized he was a product of Lemieux. Mario 199 points and next closest person Rob Brown literally 84 points behind him. Mario was his team at that time and Gretzky's big numbers team he played with players on his line in the Hall of Fame like Kurri and Anderson.