Test hopeful Alex Doolan has smashed an unbeaten century to put Tasmania within touching distance of a hard-earned Sheffield Shield victory over NSW on the final day at Blacktown.

The defending Shield champions appeared in major trouble when they resumed at 1-18 on Saturday with stoic opener Ed Cowan already back in the shed.

But Doolan’s brilliant 117 not out from 175 balls has steered Tasmania to 2-240 at tea on day four, with just 55 runs required for the win.

Doolan was being talked about for a Test call-up last summer, and is in the frame again for the Ashes, with at least one spot in the Australian batting line-up there for the taking.

It would seem his Tigers’ teammate George Bailey has a stranglehold on the vacant No.6 spot for the first Test in Brisbane, but Doolan’s sixth first-class ton in difficult batting conditions will ensure he’s well and truly in the conversation for a Test call-up.

Doolan scored a fine 56 in the first innings and has been the standout batsman in the game on a slow Blacktown pitch, even overshadowing Michael Clarke, who made 88 in NSW’s first dig.

Tasmania had a clear plan to attack their target of 295 when they resumed on day four, with Doolan executing the game plan perfectly.

Turning 28 later this month, Doolan played smart but elegant cricket, stroking 17 boundaries.

Doolan was well supported by Ben Dunk, who made 67 after being promoted to open, and Jonathan Wells (45no).

Launceston-born Doolan will have another important chance to impress selectors on his home-State pitch in Hobart, when he lines-up for Australia A against England.

A big hundred against the Ashes opposition on the eve of the series will make a big statement.

Doolan smashed three consecutive fours off NSW quick Josh Hazlewood and Dunk brought up his 50 with the second of two big sixes down the ground from spinner Nathan Lyon (0-58 from 17).

Doug Bollinger (1-61 from 18), who took six wickets in the first innings, stepped up for NSW to trap Dunk lbw but, with Doolan at the crease and Jordan Silk to come, Tasmania are almost home, despite the 49-run first-innings deficit they gave up.

Australian captain Michael Clarke spent some time off the field for NSW on day four, but appears untroubled by his back.