Two hat-tricks in one game is no mean feat but Mitchell Starc has been warned he must bowl smarter on a lively Gabba deck in the first Ashes Test.

Former Test seamer Stuart Clark revealed Western Australian coach Justin Langer had told him his batsmen were terrified by NSW left-arm speedster Starc in his Sheffield Shield blitz in Sydney.

Mitchell Starc took two hat-tricks in NSW's win over WA. Credit:AAP

Starc inspired the Blues' 171-run win by becoming the first person to nab two hat-tricks in the same first-class match in Australia and the first Aussie in more than 100 years to achieve the feat.

Yet Clark believed Starc would need to bowl better if he was to maximise a juicy Gabba deck expected for the first Ashes Test starting on November 23.