Kewell scored the only goal of the game as Australia move four points clear at the top of Group 1 in the Asian qualifying zone.
However, Australia survived a second half fight-back from Iraq as goalkeeper Mark Schwarzer was forced to make a string of saves and captain Kewell admits his side were fortunate.
"We know what we have to do," said Kewell on Sky Sports News. "It is always difficult going into World Cup qualifying group stages.
"We rode are luck. Iraq had a lot of good chances, but at the end of the day we got the goal and the three points."
And Schwarzer, who has seen Australia go six consecutive games without conceding, has also admitted his delight at the three points.
"But the most important thing is the result and we won the game.
"I'm glad we kept a clean sheet and won the game in difficult conditions.
"It's nice that the defence is firm, but it's not just the defence it is the whole team."