Steve Smith's team were knocked out by India in a do-or-die showdown in Mohali on Sunday, leaving their hopes of winning their first World T20 trophy once again in tatters.
"First of all, our selection was wrong in my opinion," Warne told cricket.com.au.
Learned to sweep by watching Younus Khan: AB de Villiers
"I don't think we got that right, we messed around with it too much rather than sticking with what's been a proven formula and we probably didn't play well enough, which is the brutal truth."
Warne said Usman Khawaja should have batted at number three and opening pair Aaron Finch and David Warner should not have been broken up.
"I don't think they should have broken up Finch and Warner and I think it upset the balance of the team," Warne said, adding that their partnership would have been an "intimidatory factor before a ball was bowled".
Afridi’s attitude was non-serious during Asia Cup and World T20: Waqar
"Those two guys had been batting together for a long time, they have done well in Twenty20, they've done well in one-day cricket, and suddenly they got spilt up.
"And I just would never, ever have left Aaron Finch out... It's not to say they didn't worry about Khawaja, but I just think the other two are more destructive."
The spin legend also queried Josh Hazlewood's selection over all-rounder John Hastings for Australia's final two matches.
"I just think because we had so much talent in our team and so much skill, they (Australia's selectors) thought 'it doesn't matter what the combinations are we're still going to do OK', but it wasn't to be," he added.
India face the West Indies in the second semi-final on Thursday for the chance to play Eoin Morgan's England team in the final on Sunday.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ