Rhys Howden and Richie Campbell, both taking part in their fourth Olympics, scored a combined seven goals in the rout.

The Sharks entered the pool knowing their hopes of reaching the quarter-finals - and pursuing the side's first Olympic medal - were already over.

Australia played with freedom and dominated every facet of the game, surging to a 7-1 halftime lead then continuing to score freely as goalkeeper Joel Dennerley produced a total of 12 saves.

A third-quarter send-off for Aidan Roach, the son of rugby league icon Steve 'Blocker' Roach, was one of few blemishes for Australia in the lopsided clash.

Earlier in the first term, Kazakhstan's Srdan Vuksanovic was also ordered to leave the pool.

Vuksanovic's reaction was a mix of rage and disbelief, with the 29-year-old hurling his cap after leaving the water.

The Sharks, whose pool featured three of the top four sides from Rio 2016, were left to lament an opening loss to Montenegro that ultimately ruined their hopes of progressing to the knockout stage.

Australia, whose tournament highlight was upsetting Croatia in a boilover, and Montenegro both banked two wins during the group stage.

Competition rules dictate that head-to-head record meant Montenegro claimed the last quarter-final spot up for grabs, although they also finished with a superior goal difference.

Australia coach Elvis Fatovic, who represented Croatia as a player at Sydney 2000 and Athens 2004, has already announced he will step down at the end of the Tokyo Games.

Australia's hopes of a medal in the sport at these Games are now in the hands of the Stingers, who face Russia in their women's quarter-final on Tuesday night.

Australian Associated Press