The Socceroos fell to a humbling 2-1 loss away to Jordan last month to leave them without a win in three Group B matches in Asian qualifying and outside the two automatic finals places.
The loss to Jordan, who have never reached the World Cup, followed a lethargic opening goalless draw away to Oman and 1-1 home stalemate against group leaders Japan.
McKay and his Australia team-mates are back in West Asia on Tuesday for the key clash in steamy Qatar, where Iraq play their home matches due to security concerns, knowing defeat could leave them struggling to reach a third consecutive World Cup.
"With the opening games that we've had so far in this group, it's built up the pressure on this game, it's a massive fixture for us and we all know that," McKay told the Football Federation Australia (FFA) website on Monday.
"We need to get three points out of it to really push our campaign back on track. We'll be ready, we've done the work and we know what we need to get the result."
McKay, currently playing for Busan IPark in South Korea, could be deployed at left-back with David Carney axed after the Jordan defeat and injuries in the squad.
The 29-year-old diminutive midfielder, who was part of the Socceroos side that edged Iraq 1-0 in extra time of their Asian Cup quarter-final last year, was happy to fill the void if required.
"It's a position I've played before and I know I can do a job. It's not my favourite position, everyone knows that, but I actually enjoy it when I get an opportunity there, it just makes me a more rounded player."
Iraq have an identical record as the Australians with two draws and a loss from their three games in the fourth stage of World Cup qualifying in the region.
Goal-scoring has been their problem with a number of missed chances in their opening 1-1 draws away to Jordan and at home to Oman.
A heavily changed, more youthful side only had themselves to blame for not grabbing at least a draw in a 1-0 loss away to Asian champions Japan last month.
The 2007 Asian champions have trudged back to Qatar from Sweden, where they suffered a 6-0 thrashing at the hands of World Cup hosts Brazil on Thursday with their Brazilian coach Zico expected to ring the changes for the Doha match.
"We left Qatar where it was 35 Celsius, travelled for 10 hours to a place where it's five Celsius and we have to go back again afterwards," Zico told Brazilian media.
"It wasn't the right moment. I wanted to play Wales and they gave me Brazil."
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