SINGAPORE - The Asian Cup heads to Australia for the first time next month with the scars of a woeful 2014 World Cup for the continent and the recurring problems of match-fixing and swift sackings leaving the tournament wide open. Holders Japan are favourites to win a record extending fifth continental title but dark clouds hang over their coach Javier Aguirre after he became embroiled in a Spanish match-fixing case dating back to his time as Real Zaragoza boss.

The Mexican has long denied any wrongdoing but the negative attention has not helped confidence in Japan, where a mixed start and the exclusion of form players, like Gamba Osaka forward Takashi Usami, have raised questions about his suitability. The pressure on Aguirre, though, is nothing like what Ange Postecoglou is under as the hosts welcome Asia's biggest tournament for the first time since joining the confederation in 2006.

Australia, runners up to Japan in 2011, won only one match in 2014, a friendly triumph over Saudi Arabia in September, with defensive lapses in the young side a glaring issue as the coach struggles to replace a golden generation which qualified for three consecutive World Cups. "Things haven't been going well prior to this tournament, we have to be brutally honest. We've probably gone a little bit backwards," former Australia goalkeeper Mark Bosnich told Reuters..

Postecoglou was in charge for the predictable three World Cup defeats in Brazil, where the Socceroos, Japan, Iran and South Korea all finished bottom of their groups as Asia failed to earn a single victory for the first time since 1990. He kept his job with the Asian showpiece in mind but a failure on home soil is sure to spell the end of his tenure.

His task is not helped by a tough Group A including a showdown against South Korea, who are now under the guidance of German Uli Stielike, one of 11 coaches appointed by the 16 finalists last year as flagging teams eyed a fresh start. Bahrain and Jordan have gone through a combined six managers since last year, while Saudi Arabia and Iraq have loaned coaches from club sides for the Jan. 9-31 tournament in a glaring example of the short-sightedness in the region's administrations.

"The coach doesn't have time to impose his style on the team and quite often he will have very little input into selecting the squad," former Australia boss Pim Verbeek said of the constant chopping and changing. Carlos Queiroz is the longest serving boss in the tournament but a lack of adequate warm-up matches leave his defensive Iran side short of quality action as they seek an attacking dimension in order to lift a fourth Asian Cup.

While they look forward to a 13th Asian Cup, Palestine are taking part in their first after overcoming a raft of player access issues to qualify by winning the Challenge Cup for emerging nations. The West Asians will do well to get anything from two former winners Iraq and Japan in Group D, with Uzbekistan, UAE and Qatar more likely to be tournament dark horses.