Tasmania will take a massive 295-run first-innings lead into day three of the Sheffield Shield match against South Australia.

Tasmania allrounder Evan Gulbis posted his maiden first-class century in style as the Tigers ended South Australia’s hopes of appearing in their first Sheffield Shield final for 18 years.

The 27-year-old produced the innings of his life in compiling 156 not out on Wednesday, the best score by a No.8 in Shield cricket.

The Tigers finished day two at Bellerive Oval on 8-507 with a lead of 295 runs on the first innings.

And the look to have extinguished any remaining hopes SA had of making the season decider in the process.

“I always knew I could bat and it was just about finding a way to do it,” he said.

“I thought I played pretty well in my last game here and I’ve built from there. Hopefully I can build on it tomorrow and make it a big one and (the record) might stay for a while.”

Following the lead set by opener Mark Cosgrove (110), who had posted his first ton for the season during the morning session, Gulbis brought up his century late in the afternoon by turning part-time spinner Tom Cooper to the leg-side for a quick single.

The former Victorian saluted his applauding teammates and embraced batting partner Tim Paine (87) in the middle of Bellerive Oval in a moment sure to erase memories of the four consecutive ducks he made during his first two Shield matches for the Tigers.

“It’s a strange game, cricket, and you never take it for granted,” Gulbis said.

“Things like that can happen. It wasn’t the way I wanted to start my career and hopefully I’ve got it a little bit more back on track.”

Gulbis hit 21 boundaries and two sixes and will resume alongside Xavier Doherty on Thursday morning after Ben Hilfenhaus (30) was bowled by Callum Ferguson (1-23) with the penultimate ball of the day.

Coming into the match the Redbacks were a chance to host the final if they won and saw other results fall their way.

But now, just halfway through the contest at Bellerive, they are a long way from securing the outright points needed to guarantee a place in the decider.

With NSW and Queensland on top in their respective matches against Western Australia and Victoria, the Redbacks need to conjure an unthinkable second-innings turnaround just to keep their season alive.

Cosgrove and Ben Dunk (72) had resumed on Wednesday and chipped away at the 213 runs required for first-innings points before Dunk scooped a catch to Cooper from Chadd Sayers’ bowling.