The young New Zealand side lost 84-81 in the last seconds but there was not much more Timmins could have done.
The towering Otago Boys' High School centre had 20 points (on 7-of-11 shooting), 13 rebounds, six blocks and four assists in a powerhouse individual performance.
It took a three on the final buzzer from brilliant Australian guard Dejan Vasiljevic to break the hearts of the gallant New Zealanders, who had fought back from a 10-point deficit after the first quarter.
Led by big men Timmins and Tai Wynyard (21 points and seven rebounds), the Junior Tall Blacks proved there is plenty of exciting talent coming through the ranks in New Zealand basketball.
Coach Judd Flavell was a mix of emotions at the end of the game - proud of his players but bitterly disappointed at the result.
''I am exceptionally proud of these boys,'' Flavell said.
''For most of them, playing on this sort of occasion and at this level is a great and new experience, and we said at the end we can hold our heads up high.
''We were in a dogfight for most of the game. In the past, we might have buckled when down but we hung in there and made it a grind. That shows good signs of our mental toughness.''
Flavell urged Basketball New Zealand and funding organisations to do more to assist in the development of a talented bunch of young men. More good players were left at home after missing the final roster.
The key was more international exposure, something that might be helped by a change in qualification for World Cups, with a move into Asia.
''Australia won the silver at the world champs and we are right there with them. Look at the talent in this group.
''We should be excited about what lies ahead of this team. Many of them are very young.''
Flavell praised the efforts of Timmins and Wynyard.
''They both played a hell of a game. They ran themselves into the ground. We went a man down early on and they all had to step up. I was just enjoying watching them take the Aussies on.''
One area that perhaps made the difference was from long range. The final dagger from Vasiljevic was one of 12 made by the Australians from 24 attempts, compared with just three of 16 from the New Zealanders.
The second Otago Boys' player in the squad, Joe Cook-Green, came off the bench to score six points.
The scoreline in the women's final was more lopsided - Australia won 98-65 - but coach Brent Matehaere, of Dunedin, was proud of the Junior Tall Ferns.
''They have been amazing right through the week, and in the face of some health issues, as well,' Matehaere said.
''We started reasonably well but they are really long and got a lot of second-chance points with rebounding putting pressure on us.
''They got away on us in the second quarter, which was frustrating. We chatted at the half and talked about doing something in the game and proving ourselves.
''We cut the score back to about 13 and had a chance to bring it back to close to single figures but we turned it over and the lead went out again. They were just a little too classy.''
Krystal Leger-Walker led the Junior Tall Ferns with 15 rebounds, while Maia Wilson added 12 points and six rebounds, and Otago's Whitnee Wehi had five rebounds.
