The Redbacks claimed an emphatic 193-run victory on Sunday when the home side, chasing an unlikely victory target of 299, capitulated for 106 in just 29.4 overs.
Pacemen Joe Mennie (4-21) and Daniel Worrall (4-33) led the charge for SA, with the former claiming two scalps in his first over.
SA will qualify for the final against first-placed Victoria if NSW draw or lose to Western Australia in Perth on Sunday, with the Blues resuming at 1-6 in pursuit of a massive 402 for victory and a berth in the decider.
The Tigers lost their top six batsmen for single digits, including two ducks to skipper George Bailey and Jordan Silk.
They lost 5-5 across four overs including opener Alex Doolan then Bailey and Jordan Silk, both caught in the slips.
Tim Paine added 26 including five boundaries before he was caught at second slip.
Batting at No.10, Sam Rainbird top-scored for the Tigers with an admirable 33 but his wicket marked the end of Tassie's Sheild season, during which they claimed just one victory and finished a distant last on the ladder.
After a lacklustre first innings' total of 225 to which Tassie replied with 332, SA hit back in their second dig reaching 406.
'LIVE' Points Table
1. VIC 60.31 Points
2. SA 47.24
3. NSW* 44.6
4. QLD 41.53
5. WA* 39.48
6. TAS 19.64
* still in play
Outright win = 6 points
Tie = 3 points
Draw = 1 point