The Boomers are out of medal contention at the FIBA World Cup, falling to a 91-80 defeat against Slovenia in Okinawa.

Slovenia outscored the Boomers by 10-points in the first quarter and, although Australia closed to within two points early in the fourth, dominated the closing stages to seal the win and remain undefeated at the tournament. 

Luka Dončić, who was in foul trouble early with three of his permitted five in the first half, dominated the final quarter defensively, restricting the Aussies to just four points through six-and-a-half-minutes of the final term.

By then, Slovenia had pushed out their lead to 15 points, which would grow to a game-high 19 as Slovenia completed a dominant victory.

Slovenia successfully stopped the Boomers' fast breaks with clever fouls, and closed off the paint to force them to shoot from outside the arc, which Australia seemed reluctant to do, attempting just 24 outside shots, scoring just eight.

Australia will still play Georgia in a dead rubber, but cannot make the quarterfinals and will be left ruing their narrow defeat against Germany that made this a must-win contest.

New York-born, 213-centimetre centre Mike Tobey had a double-double of 18 points and 12 rebounds, while Dallas Mavericks' NBA All Star Dončić ended with 20-points.

Josh Giddey had eight rebounds and a game-high 25 points, 13 of which came in a brilliant third quarter as the Aussies closed to within four points, while Patty Mills ended with 17 points.

Slovenia were overjoyed with their win, extracting some revenge on Australia for their bronze medal defeat at the Tokyo Olympics.

"Preparation for the Olympics starts now, we learned a lot," Boomers coach Brian Goorjian said.

 "I think we're in a process of change in style of play, both offensively and defensively.

"Some big decisions are ahead but I like what's in front of me."

The Boomers were blown away in the first quarter, Slovenia establishing a 10-point lead at the first change, although the Boomers edged the second term to trail by nine at half-time.

Giddey, playing in his first World Cup, caught fire in the third term, scoring 13 points as Dončić struggled with four personal fouls and spent time off the court as Australia closed to within four points by the final change.

However, a brilliant three-point shooting display in the final term saw Slovenia push the margin back out to double figures — with the Boomers failing to make their mark.