Leading 3-0 soon on goals from Glenn Simpson (fourth minute), Jacob Whetton (29th) and Russell Ford (37th), Australia were jostled by two goals in successive minutes from Sebastian Dockier (38th and 39th), who gave Belgium something to cheer in their maiden appearance in the Champions Trophy.
Just 45 seconds separated the two goals from Dockier, who first deflected in a cross and then sent a stinging shot past custodian Andrew Charter, who came in as a substitute goalkeeper after half-time and conceded two goals within four minutes.
Striker Christopher Ciriello, who returned to the pitch in the second half despite suffering a broken nose early in the game, fired Australia's fourth goal to again lift the spirits of a partisan home crowd.
In another Pool A match, New Zealand gave Olympic champions Germany a scare before the world's top-ranked team prevailed 3-2.
Staging a fine rally in the closing stages after slipping behind by three goals at half-time, New Zealand came close to equalising, only to see the strikers miss a chance in the dying seconds.
Earlier, Olympic Games silver medallists Netherlands launched the tournament with a 3-1 come-from-behind victory over Pakistan, who stunned the Dutch defence midway in the first session to open the scoring through nippy striker Muhammad Waqas.
But the Dutch penalty corner drills then penetrated three times to take full points from the Pool B fixture. More
