New South Wales 447 for 9 dec and 203 for 2 (Hackney 98*, MacDonald 61) lead South Australia 309 for 7 dec (Lehmann 101*, Drew 85, Tremain 3-75, Hadley 3-75) by 341 runs

An audacious declaration from South Australia's Jake Lehmann and a career-best score for New South Wales opener Ryan Hackney has brought the final-round Sheffield Shield match at Karen Rolton Oval to life on day three.

On a docile pitch that had produced just 16 wickets in eight sessions, Lehmann declared South Australia's first innings closed at 309 for 7, 138 runs in arrears of the visitors, just after posting his ninth first-class century.

The Blues took up the baton in the final session thumping 203 for 2 off just 42 overs for a lead of 341. Hackney led the way in his fifth Shield match, ending the day unbeaten on 98 not out. After also scoring a half-century in the first innings, he struck 13 boundaries and a six in his 115-ball knock. Debutant opener Blake MacDonald also made 61 as the inexperienced pair added 143 for the first wicket.

Ollie Davies helped the scoring along in the final half-hour with a whirlwind 31 off just 24 balls.

Earlier, South Australia scored at just over three runs an over before declaring when their 100-over bonus point period ended.

Lehmann impressed with an unbeaten 101, clocking up 13 boundaries in his 178-ball stay at the crease. Daniel Drew was more sedate during his four-and-half-hour innings of 85.

Experienced paceman Chris Tremain and first-gamer Ryan Hadley both picked up 3 for 75 for the Blues. The inexperienced NSW side must collect victory in Adelaide to avoid a winless campaign for the first time in a 10-match season, while South Australia are seeking to hold off Tasmania and finish fourth.