South Australia's bid for a first limited-overs finals appearance in seven years has received another shot in the arm tonight with a 34-run victory over a disappointing Tasmania here in Adelaide.

Though rearguard action from the visitors denied the Redbacks a potentially invaluable bonus point, the win still hoisted them to second position on the ING Cup table alongside Western Australia with only two preliminary rounds remaining. The pair are each five points behind pacesetter Queensland on the table and four ahead of New South Wales, the only other candidate for a role in the deciders later this month.

With the Redbacks in the midst of that four-way battle for the two finals positions on offer - and the Tigers destined to finish at or near the table's foot - it wasn't too hard to discern which team was which in this encounter.

Especially at the start of the evening session. Which was when in-form all-rounder Mike Smith (3/32) laid waste to Tasmania's pursuit of a tally of 7/250 on a true pitch.

Smith has been in exceptional touch this season, and his form peaked earlier this week when his bowling floored Queensland in a Pura Cup match in Brisbane. The destructive burst that netted the wickets of Michael Dighton (35), Shane Watson (5) and Jamie Cox (0) in the space of eight deliveries effectively settled this contest too.

Dighton fell to a brilliant catch as he cut with force toward Ben Johnson, diving forward and fractionally to his left, at deep backward point. Watson and Cox were then undone as they mistimed drives at Smith leg cutters to feather catches to wicketkeeper Graham Manou.

At 4/60 in the 21st over, the lights were already being turned out on Tasmania on a perfect evening in Adelaide.

Smith then returned later in the innings with a direct hit run out to remove Scott Kremerskothen (12), linking with Greg Blewett (2/41) and Paul Wilson (2/30) to mop up the remnants of the Tigers' middle and lower order.

Albeit that Daniel Marsh (51) and Michael Di Venuto (44) - a former South Australian and the target of a South Australian offer in the off-season respectively - rejuvenated their side's cause with a stubborn 97-run liaison for the fifth wicket. And that, for the second time this season, the Tigers' last wicket pair thwarted the South Australians' best-laid plans at landing a bonus point with a bout of breezy hitting.

Earlier, the platform for South Australia's total had been assembled by Blewett (65) and David Fitzgerald (44) in a 93-run stand that represented the state's best association for the opening wicket in one-day matches this summer.

Their driving, against a steady attack, was outstanding and their penchant for working singles equally impressive. Albeit that both were run out in the name of adding extra numbers to the scoreboard: Fitzgerald by a direct hit from Scott Mason at cover point and Blewett to a superb save and back handed throw as bowler Marsh (2/45) dived along the ground to his right.

With Darren Lehmann answering an SOS from Australia, the middle and closing stages of the Redbacks' innings were devoid of their usual acceleration. But handy contributions from Chris Davies (45), Nathan Adcock (40) and Johnson (31) kept the innings bubbling nonetheless.

What Tasmania would have given for so consistent an upper order performance. After losing the toss for the sixth time in eight one-day matches this season, the Tigers used their fifth different opening batting combination. But it didn't spark a significant change of fortune.