1990 began promisingly enough for Dunstall. In Round 1, in the Grand Final rematch against at Waverley Park, he kicked a then career-best 12 goals after being held goalless in the first quarter. Hawthorn went on to thrash the Cats by 115 points. In Round 4 against at Princes Park in wet conditions, Dunstall kicked 8 goals, bringing up his 500th career goal in the process, as the Hawks won by 82 points. But in Round 9 against , Dunstall was injured in the first quarter. He fell heavily on an opponent's boot and sustained a serious injury at the front of his head. He was taken from the ground and admitted to The Alfred Hospital. At that stage of the season Dunstall had kicked 41 goals. The injury would cause him to miss the next four matches. After his return in Round 14, he kicked a further 42 goals, including 11 goals against Collingwood in Round 20. On the Footy show after the 1990 AFL Grand Final, Leigh Matthews said that he was glad Hawthorn got knocked out of the finals, because Dunstall always seemed to kick a huge number of goals against the recently crowned premiers.