Tasmania 27 for 3 (McAndrew 3-8) trail South Australia 271 (McSweeney 117, Carlisle 3-62, Webster 3-63, Elliott 3-65) by 244 runs

Nathan McSweeney's century helped South Australia stand up to ladder-leaders Tasmania as they push to end their Sheffield Shield season on a high at Blundstone Arena.

McSweeney, who has previously been mentioned by national selector George Bailey, posted 117 from 174 balls, just one run shy of his highest first-class score, as the Redbacks were dismissed for 271 after being sent in on a very green pitch.

In reply, Tasmania were wobbling on 27 for 3 at stumps on day one after paceman Nathan McAndrew hit his stride to put his underdog team on top ahead of day two.

McSweeney had little help from his team-mates in the batting order, with no other Redback passing 30 runs. The 25-year-old rode his luck after being dropped by Caleb Jewell on 15 in the over before lunch. When the South Australian innings spun into crisis, McSweeney made Tasmania pay.

He was on 47 when No.10 Brendan Doggett came in, the Redbacks well and truly into the bowlers at 195 for 8. McSweeney and Doggett forged a 62-run partnership that pulled South Australia back from the brink, with Doggett pitching in only one of those runs.

McSweeney brought up his fifth Shield century with two runs off Beau Webster in the 71st over, though he needed to dive to avoid being run out when the ball was thrown in from deep extra cover. McSweeney almost dragged on from the next ball, but forged on, adding two more boundaries to his 15 for the day.

For Tasmania, opener Matthew Wade and Gabe Bell were unbeaten at the crease at stumps but their side appeared on the back foot following McAndrew's early carnage.

Fifth-placed South Australia are out of contention for the Sheffield Shield final but a win could deny Tasmania the chance to host the decider next week.