Jockey Craig Williams is convinced Dunaden can show his true colours when he bids for back-to-back wins in the Hong Kong Vase at Sha Tin on Sunday week.

The Mikel Delzangles-trained six-year-old claimed the esteemed Group One in some style last season, but must put behind him a disappointing run in the Melbourne Cup on November 6.

Dunaden finished 14th in his quest to win the Flemington highlight a second time, but Williams is adamant there were excuses that day.

"The slow pace was very much against Dunaden in the Melbourne Cup so I wouldn't be too concerned about that run," he said.

"There is also an argument to say that 2400 metres (a mile and a half) is his best distance."