Tasmanian captain Jamie Cox shrugged off a batting form slump in heroic style today - scoring a marathon unbeaten century to put his side in a commanding position after day two of its crucial Pura Cup game against South Australia at Adelaide Oval.

In reply to SA's first innings 200, the Tigers were 3-291 at stumps, with Cox unbeaten on 144 after batting through the entire day, and Daniel Marsh with him at the crease on 63.

The two first innings points, obtained early in the final session, brought the Tigers level with SA in second place on the Pura Cup table.

If Tasmania can push home its advantage in the next two days and claim an outright win it will be a strong chance of making the Pura Cup final.

The Tigers started the day at 1-26, but Cox and Michael Dighton took the score to 147 before all-rounder Mike Smith had Dighton caught at mid-on for 76 midway through the middle session.

Michael Divenuto (five) fell to left arm spinner Bradley Young in the following over, but they were the only two wickets to fall for the day, as Marsh and Cox put on an unbroken stand of 139 in the final three hours to crush the spirit of the Redbacks attack.

The normally prolific Cox has struggled for runs this season, particularly since Christmas, and had only averaged 29 in 2001/02 before this match, with his last century, a score of 107, coming against New South Wales at the SCG in the opening match of the season.

He said the recent struggle for runs and the importance of this match to Tasmania's finals hopes meant he rated today's innings among the best of his career.

"Given the fact that I've been struggling ... they could be very crucial runs. The game is going to be well set up for us," Cox said.

"That's exactly why today was so special, it's nice to know I'm capable of doing it again and remember what it feels like. Cricket's been a hard game lately."

SA captain Greg Blewett used eight bowlers today in an attempt to turn the match the Redbacks' way, but strangely only introduced veteran leg spinner Peter McIntyre to the attack as the seventh bowler with the score already 3-179, despite there being plenty of turn in the pitch.

Cox said the Tasmanian plan would be to try to build a big first innings lead so the Tigers would not need to bat again, forcing SA to bat last on what was likely to be a wearing pitch.

"Hopefully it will be very tricky, hopefully very up and down," he said.

"It's still a good batting wicket if it's respected, but hopefully with a bit more sun it will wear it out."

© 2002 AAP