Australian coach Brian Goorjian saw enough in a messy 84-67 win over Nigeria to assure him their quest for a maiden Olympic basketball medal is on track in Tokyo.
Flagbearer Patty Mills led the side with 25 points on five-of-eight three point shooting as the Boomers kept Nigeria to 27 points in the second half.
The Boomers forced 24 turnovers and constantly threatened to sneak away, only for Nigeria to rally and make it a five-point game at the final break.
A nervy finish looked inevitable before a costly unsportsmanlike foul by Chimezie Metu on Matthew Dellavedova (eight points, three rebounds, three assists) opened the door for the Boomers.
Metu was also given a technical foul for remonstrating in what became a four-point play that saw the forward ejected.
Mills nailed another three-pointer soon after as the lead swelled into double digits for the first time.
The Boomers, who had 21 turnovers of their own and shot at 39 per cent from the field, were also let off the hook by Nigeria's poor 12-of-24 free throw shooting.
"The areas of concern for us in the game were expected; we were choppy in the half-court ... and the flow of the game we made a lot of poor decisions," Goorjian said.
"But this group ... we've focused on defence and I thought that was good and got better and was the reason for the victory."
The Boomers' torturous run of near misses at major events - they finished fourth at the last World Cup and Olympics - is driving this side in what will likely be the last shot at Games gold for Mills, Dellavedova, Joe Ingles and Aron Baynes.
But they arrived in Japan fresh off warm-up game wins over Argentina, Nigeria and the red-hot gold medal favourites the United States to prove they are legitimate prospects.
"We're going to have to get a lot better but you're going to see it in most teams in the tournament," Goorjian said.
"The culture, the mentality, the commitment, the buy-in and areas right now you can control is huge to keep us in this thing as we get better."
Goorjian used all 12 players, fit-again Dante Exum (11 points, five rebounds, three assist) was at times over-exuberant in adding five turnovers, while Matisse Thybulle (nine points, four rebounds, five steals) was another point of difference.
Rookie Josh Green also defended well in a a crucial stretch to end the third term Nick Kay had 10 points and eight rebounds while Ingles scored 11 points.
They next face Italy on Wednesday and Germany on Saturday, with the top two sides from each pool progressing to a knockout quarter-final.