The Socceroos are gunning to keep their 100 percent World Cup qualifying record intact in Bahrain on Wednesday, while Japan have injury worries ahead of their critical match in Doha against Qatar.

Australia go into their clash as the only Asian team to have maximum points, after beating Qatar and Uzbekistan, and are boosted by the return from injury of senior players Mark Bresciano and Harry Kewell.

On the downside, they are expected to be without Blackburn`s Vince Grella after he picked up a hamstring injury in their loss to Chelsea last week.

Coach Pim Verbeek said that Kewell and Bresciano`s ability to play as left-sided attackers eased the likely loss of Grella and Scott Chipperfield.

`They are fantastic players and they can play on the left side, so although Chipperfield is gone, with Harry back and Bresciano back -- if they are all fit -- I am very happy with my players,` Verbeek said.

Bahrain are struggling to make an impact on the group with just one point so far, the same as Uzbekistan.

Japan have four points from two games and are level with Qatar in Group A, although the Gulf side have played three times.

A win for the Japanese would give them a three point cushion over Qatar as they try to keep tabs on Australia with only the top two from each group qualifying for South Africa 2010.

But Japan have been hit by injuries, with Celtic midfielder Shunsuke Nakamura struggling with a left knee ligament problem.

First-choice goalkeeper Seigo Narazaki is a definite non-starter after knocking his ankle, as is star defender Yuji Nakazawa, who has strained his right thigh.

Japan coach Takeshi Okada, under pressure after a run of uninspiring results, has selected Europe-based midfielders Daisuke Matsui of Saint-Etienne and VfL Wolfsburg`s Makoto Hasebe among his mainly J.League-based squad.

`I have selected members who understand the way this team plays and who are highly motivated to represent Japan with determination to win,` he said.

`Qatar players have individual skills and it will be tough if we are outdone in one-on-one situations. We cannot beat them if we don`t outrun them.`

Qatar coach Bruno Metsu has cracked the whip by dropping Hussein Yasser, with the playmaker lacking match practice after falling out of favour with his club Al Ahly.

`We are now trying to give a chance to new players,` said Metsu, who has called up Mohamed Omer and Hassan Al Haidous for the first time.

`Winning the match (against Japan) is very important as it will consolidate our chances for qualifying for the World Cup.`

In Group B, South Korea, who made the semi-finals on home turf in 2002, face a daunting game against Saudi Arabia in Riyadh while Ali Daei`s Iran play the United Arab Emirates in Abu Dhabi.

The group is finely poised with South Korea, Iran and Saudi Arabia on four points after two games while North Korea have four points after three matches.

UAE desperately need a result after failing to pick up a point in their three games so far.

South Korea are likely to give a start to veteran goalkeeper Lee Woon-Jae, selected for the first since he was banned for a year over a nightclub incident.

`I think he has fully reflected on what he did. He has also played well in the domestic league,` said coach Huh Jung-Moo, who watched his team draw 1-1 with Qatar in a friendly over the weekend.

Manchester United`s Park Ji-Sung, former Tottenham star Lee Young-Pyo and Park Chu-Young of AS Monaco give the side a European feel.

The Saudis could be without Asian Player of the Year Yasser Al Qahtani, who has a groin strain.