Rocca and David King, who slotted through five goals but was also reported for striking Andrew Dimattina, were on fire, as the Roos remained undefeated, holding out the youthful Magpies 18.12. (120) to 14.8. (92).
Kangaroos skipper Wayne Carey was also at his brilliant best, coming off the bench in the third quarter to play in key part in his side's victory, but key defender Mick Martyn left the field in the first term, apparently with a hamstring injury.
Carey has had an extended pre-season to protect his ageing body but "The King's" superb cameo performance overshadowed a best-afield effort from Collingwood captain Nathan Buckley.
The Kangaroos kicked clear in the third term to lead by 33 points, but Collingwood then scored five of the next six goals to trail by only eight points early in the final term.
A dubious free kick to Jess Sinclair in the goalsquare gave the Roos a bigger buffer, but Shane O'Bree goaled to again pressure the Kangaroos.
Carey then kicked a long goal and short-passed to Rocca, who made the margin 20 points and snuffed out the Collingwood challenge.
Rocca was booed by Collingwood fans when he lined up for goal in the first quarter and kicked a behind, his first goal came from a booming 50m kick in the second quarter.
Sav then took a spectacular overhead mark a few minutes later to ensure the 'Roos went into the main break with the lead.
The Kangaroos now take on Port Adelaide next weekend for a spot in the Ansett Cup grand final, while the Magpies, who scored impressive victories over St Kilda and West Coast in their first two pre-season matches, head for the practice match circuit before their first round home and away match against Hawthorn at the MCG.
MATCH DETAILS:
KANGAROOS: 5.3, 9.5, 13.10, 18.12 (120)
COLLINGWOOD: 1.2, 7.4, 11.8, 14. 8 (92)
Goals: Kangaroos: King 5, Rocca 4, Blakey 2, Harvey 2, Carey, Lange, Pickett, Simpson, Sinclair. Collingwood: Buckley 3, Lane 3, Tarrant 3, Burns, Molloy, O'Bree, Rocca, Shaw.
Best: Kangaroos: King, Stevens, McCartney, Harris, Carey. Collingwood: Buckley, Ukovic, O'Bree, Rocca, Johnson.
Umpires: Kennedy, Ellis, Woodcock.
Official crowd: 28,983 at Colonial Stadium.
