The unbeaten mare now has 14 Group One wins, equal with Kingston Town as the most in Australian history.
A capacity crowd cheered her home in the William Reid (1200m) as she stretched out in the straight and extended her lead over stablemate Karuta Queen to win by more than four lengths.
Karuta Queen had led early but once Black Caviar moved up on the turn, the field strung out and she went to the line to win easily.
Trainer Peter Moody said Black Caviar was in better shape now than she was a year ago before she went to Royal Ascot for a narrow win in the Diamond Jubilee Stakes.
"It's scary how well she's going," Moody said.
"The way she let down and quickened - not many can sit down and sprint when she says go. I'm a bit lost for words."
Jockey Luke Nolen said the mare felt as good as she had ever done.
"She didn't disappoint anyone here today," he said.
"She felt amazing to me. She floated into the race on her own accord.
"It's a privilege to be part of such a wonderful racing story, an Australian sporting story."