Hrovat turned in a dynamic display in the midfield with 34 disposals and 17-year-old Billings booted five goals in round three of the 2012 NAB AFL Under-18 Championships.
Metro kicked six goals to two in the first quarter to set up the result, holding on to win 16.7 (103) to 12.13 (85).
Exceptional toughness at the contest and an ability to work overtime in the middle were features of Hrovat's game.
Among the standouts for Vic Metro were teammates Josh Kelly (21 touches) and potential North Melbourne father/son pick Luke McDonald.
Billings is a classy left-footer in the mould of St Kilda's Nick Dal Santo and his five-goal haul suggested he will be high on recruiter's lists come draft day next year.
South Australia's Matthew Scharenberg was another 17-year-old to impress recruiters. He showed poise in a stellar game across half-back, where he picked up 25 disposals.
Teammate Matthew McDonough was a focal point up forward early, keeping his team in the contest by booting five first-half goals.
McDonough stands just 180cm tall but is accurate in front of the sticks and finished with six goals to be one of the Croweaters' strongest performers.
At the other end of the spectrum, ruckman Brodie Grundy (three goals) stepped up to kick two pivotal goals before three-quarter time to ensure his side remained within striking distance.
Two late withdrawals hurt SA's chances: in-form forward Troy Menzel (younger brother of Geelong's Daniel) and midfield jet Jimmy Toumpas.
SOUTH AUSTRALIA 2.2 7.4 10.7 12.13 (85)
VIC METRO 6.3 9.5 14.5 16.7 (103)
GOALS
South Australia: McDonough 6, Grundy 3, Stark, Gill, O'Brien
Vic Metro: Billings 5, Hunter 2, Macrae 2, O'Rourke, Haynes, Ballard, Daniher, Salem, Lennon, Tyquin
BEST
South Australia: Kennedy, Scharenberg, Stark, McDonough, Colquhoun, Montgomery
Vic Metro: Hrovat, McDonald, Billings, Vlastuin, O'Rourke, McKenzie, Kelly
