Australia qualified for the 2014 World Cup by beating Iraq 1-0 on Tuesday, with Josh Kennedy heading home the winner in the 83rd minute to reward a bold substitution by coach Holger Osieck.

Osieck made the surprising decision to take off veteran Tim Cahill and replace him with Kennedy, and the decision paid dividends when Mark Bresciano chipped a cross into the box, where the tall striker took advantage of lax marking to head past Noor Sabri in the Iraq goal.

The goal sparked euphoria among the sodden but exultant home crowd of 80,523, curing the heightening anxiety among fans as the minutes ticked by without Australia being able to find a way through Iraq's defense.

A draw would have left Australia at the mercy of the outcome of the Jordan-Oman game later in the day, with a likely relegation to third place in the group and a further playoff round. Jordan beat Oman 1-0 to finish third in the group and book its place in the Asian zone playoff against Uzbekistan.

Kennedy's goal meant Australia qualified directly for its third straight World Cup.

''I'm proud of everybody,'' said captain Lucas Neill. ''It's been a really tough campaign. We've stuck at it, showed mental strength.

''Sorry, it wasn't pretty. But we've beaten what was in front of us and pushed ourselves on to a very exciting tournament.''

The Socceroos won just one of their first six games in the final stage of Asian qualifying, putting their Brazil ambitions in jeopardy, but home wins over Jordan and Iraq delivered a place in Brazil for the veteran squad, which includes Bresciano, Mark Schwarzer, Lucas Neill and Cahill in the twilight of their careers.

''The boys did really well in the final stage of the campaign, it was a great effort,'' said Osieck. ''We really grew together as a team, we presented ourselves as a unit, and the reward today was that we could qualify for the World Cup.''

''It gave me a beautiful feeling and I must admit that I'm proud to be part of this.

''I know there's going to be a tough year ahead but tonight we have the right and privilege to enjoy our qualification.''

Australia started the game positively and had the first good scoring chance in the third minute with Cahill stinging the palms of Iraqi keeper Abbas Noor's goal from 10 meters, after some clever build up play from winger Robbie Kruse.

In the 15th minute Sasa Ognenovski spurned a good chance when he headed over the bar from fellow central defender Neill's chipped cross.

Cahill too had a good chance when Matt McKay's cross from the left floated over the defense to the back post, and Cahill's acrobatic effort to hook the ball over his left shoulder went just wide.

Iraq, missing several of its best players, managed just one shot in the opening half which failed to test Schwarzer.

The former Asian champions qualifying hopes ended last week in a defeat to already-qualified Japan in Doha, and they missed captain and striker Younis Mahmood and veteran midfielder organizer Nashat Akram, who didn't travel to Australia.

The visitors started the second half brightly with midfielder Saif Salman forcing Schwarzer to dive to his left to stop his low drive from 25 meters.

In the 57th minute, Bresciano shot narrowly over from just outside the box as the hosts looked to up the pressure on the Iraq backline.

Australia named an unchanged lineup for the third successive game after an impressive 1-1 draw away to Japan and a 4-0 rout of Jordan in Melbourne last week.

On the hour Australia coach Holger Oseick brought on Glasgow Celtic's Tom Rogic for Brett Holman and the change almost paid immediate dividends with Rogic bursting into the box, but he miscued his shot.

Australia put the ball in the net in the 65th minute, but Kruse's volley from outside the box was disallowed by Iranian referee Faghani Alireza who saw a foul by Ognenovski in the lead up.

Australia continued to press but couldn't find the breakthrough, prompting Osieck to substitute Cahill for Nagoya Grampus striker Kennedy.

Cahill was less than impressed with the decision, storming past the German coach to take his place on the bench, but the substitution proved inspiring.

''You have to understand that no player wants to come off but it's my prerogative as a coach to substitute players,'' said Osieck ''You can see that after the game he was one of the happiest players, he even sat on my shoulders. But he's a lightweight, if it had been (Sasa) Ognenovski it would have been a different matter.''

The hosts survived some nervous final minutes as Iraq pressed forward and created opportunities, but some last-ditch defending preserved the famous victory.

Iraq coach Vladimir Petrovic paid credit to Australia and was pleased with the efforts of a largely second-string young team.

''I want to say well done to Australia for qualifying for the World Cup,'' he said. ''We have young players that proved today that they can do the job. The luck wasn't with us.''