LIKELY first-round draft picks Jye Amiss and Arlo Draper were injured in Saturday's NAB AFL Under-19 curtain-raiser at Optus Stadium as Western Australia claimed a five-point win with a final-minute goal.

The local side backed up its win over South Australia last month with an exciting win ahead of the Melbourne and Western Bulldogs premiership decider when versatile tall Jacob van Rooyen pushed forward to kick a goal to put his side ahead with less than a minute on the clock.

The game wasn't without injuries to the talented pair who will end their draft seasons with fitness issues. WA key forward Amiss, who booted 51 goals in the colts' season for East Perth, hurt his knee in the first quarter but played on after having it strapped.

However Amiss, who shapes as a potential top-10 pick, had his day cut short in the second term with the 195cm prospect sitting out the rest of the contest.

Western Australia's Jye Amiss kicks the ball during the 2021 U19 Championship against South Australia on September 25, 2021. Picture: AFL Photos

Draper has spent most of this season playing as a midfielder and half-forward this season but was stationed in defence for South Australia on Saturday afternoon before ending the day with his right arm in a sling.

CAL TWOMEY'S AUGUST FORM GUIDE Best draft prospects ranked

It is a blow for the talented prospect who is likely to be picked inside the first round at November's draft.

South Australia's Arlo Draper kicks the ball during the U19 Championship match against Western Australia on September 25, 2021. Picture: AFL Photos

van Rooyen's end to the game closed off a performance where he had spent most of the game in defence as he continues to push his case to be top-20 pick.

West Australian teammate Matt Johnson further showcased his capabilities through the midfield with 21 disposals and five clearances to claim best afield honours, while livewire small forward Arthur Jones kicked two goals from 15 disposals. 

Western Australia's Matthew Johnson with his BOG medal after the 2021 U19 Challenge match against South Australia on September 25, 2021. Picture: AFL Photos

Blayne O'Loughlin, the nephew of Sydney great Michael, was South Australia's leading ball-winner with 22 disposals and was named his side's best while fellow Adelaide Next Generation Academy talent Isaiah Dudley booted three goals. 

INDICATIVE DRAFT ORDER Your club's picks as they stand

South Australia's Blayne O'Loughlin poses for a photo after the 2021 U19 Championship match against Western Australia on September 25, 2021. Picture: AFL Photos

WESTERN AUSTRALIA               2.4        5.5       6.9       8.11 (59)
SOUTH AUSTRALIA                    0.2        3.2       5.4       8.6 (54)

GOALS
Western Australia:  Jones 2, Farmer, Harbour, Hough, van Rooyen, Stretch, Bourne,
South Australia: Dudley 3, Owens 2, Jackson, Steene, Lemmey