In his second year with the Lakers, under new coach Joe Mullaney, Chamberlain began the season strongly, averaging 32.2 points per game and 20.6 rebounds per game over the first nine games of the season. During the ninth game, however, he had a serious knee injury, suffering a total rupture of the patellar tendon at the base of his right kneecap, and missed the next several months before appearing in the final three games of the 82-game regular season. Owing to his strong start, he still managed to put up a season average 27.3 points, 18.4 rebounds and 4.1 assists per game. It was, however, the first season in which he failed to reach 20 rebounds per game.