Radhi Shenaishil's men upset Iran 7-6 on penalties after their controversial last-eight clash finished locked at 3-3 after extra time.
But Iran appealed the result in the post-match, claiming Iraq fielded an ineligible player.
It meant Shenaishil, his team and their opponents were left waiting until just over 24 hours prior to the match to decide who would be in the semi-final.
Iraq's place was finally confirmed on Sunday, allowing them to prepare for the Australia Day clash at ANZ Stadium.
They meet opponents South Korea who will go in as favourites, having finished top of Group A and had a day's extra rest.
Son Heung-min was South Korea's hero in the quarter-finals, netting an extra-time brace in a 2-0 win over Uzbekistan.
South Korea have a remarkable head-to-head record against Iraq.
They have lost just once in 16 meetings between the nations, although 10 have ended in draws.
But Iraq forward Younis Mahmoud is focusing on happy memories, wanting a repeat of the 2007 Asian Cup semi-final.
Then, Iraq claimed a 4-3 penalty shoot-out victory after the clash finished 0-0.
"Korea are a very strong team and a good team," Mahmoud said.
"But my memory is going back to 2007 when we played them in the semi-final. I hope 2007 can happen again.”
Impressively, Uli Stielike's South Korea are yet to concede a goal at the tournament.
They went through the group stage with three 1-0 wins, and then held Uzbekistan at bay.
While Iraq were runners-up in 2007, South Korea's last appearance in the final was in 1988.
The South Koreans deserve to go into the clash as favourites, and how big an impact Iraq's unusual preparation and testy quarter-final have could be decisive.
