Ben Crocker kicked a goal with 20 seconds remaining to give Vic Metro an unlikely win over South Australia to round out its NAB AFL Under-18 Championships in style on Wednesday.

Crocker roved a ball that spilled over the back of a big pack and kicked the match-winner from point-blank range to give Vic Metro a 10.6 (66) to 8.13 (61) victory.

It was its second win of the carnival and came after trailing by 23 points at half-time and 13 points at the last change.

Metro lost the inside 50 count 48-25 and played a poor first half, but kicked five goals to two in the final quarter to steal victory.

South Australia also finished the carnival with two wins from its five matches after winning the title the past two years.

Exciting prospect Harley Balic was supreme for Vic Metro, lifting in the final quarter, while Jade Gresham was also hugely instrumental in the turnaround. 

Both finished with 22 disposals, while Crocker and Hisham Kerbatieh kicked three goals apiece. 

Northern Knights captain Gresham was strong for most of the contest at Etihad Stadium and helped turn the tide. 

His brilliant goal in the third term was a highlight, picking up a bouncing ball, going to ground and bobbing straight back to his feet to evade a defender and kick truly from close range. 

Gresham added six marks and five tackles to his day's work, and along with Balic would have impressed AFL scouts.

While missed opportunities in the first half came back to bite them, South Australia was terrific in defeat.

Luke Partington continued his strong championships with a team-high 20 disposals, as well as six tackles and six clearances. 

Jadyn Brind added a goal to his 18 disposals and was prominent with his defensive pressure.

Maris Olekalns looked like he'd give SA the win when he put his team in front with two minutes remaining, but Crocker's last-gasp effort won the day. 

VIC METRO                 0.1   1.4   5.5    10.6 (66)
SOUTH AUSTRALIA    3.6   4.9   6.10   8.13 (61) 

GOALS
Vic Metro: Crocker 3, Kerbatieh 3, Gresham, Batty, Gallucci, Moore
South Australia: Ladhams 2, Brind, Smelling, Olekalns, Redman, Tahana, Scharenberg

BEST
South Australia: Partington, Milera, Tahana, Combe, Parrella
Vic Metro: Gresham, Gallucci, Balic, Moore, Smith, Silvagni