Beginning from barrier five, he was able to settle three back on the pegs after a fast opening quarter.
Race favourite Divine State ran along in front at a strong speed and had almost all the field in single file.
Geoff Simpson peeled Castalong Shadow off the pegs with 500 metres to travel and at almost the same time Divine State started to go backwards.
Sprinting strongly, Castalong Shadow got home to win by 7.3 metres in 1:55.2.
This was the son of Shadow Play's third win from five starts and takes his earnings to $59,550.
Bred by L Favier and D Lewis, Castalong Shadow is the first foal out of Leslie Jay who is a Grinfromeartoear three quarter sister to Australian Two Year Old Filly Of The Year Lady Euthenia.
While with only four crops old enough to race, Shadow Play has now sired two Bathurst Gold Crown winners which is a great achievement.