NSW face a nervous final day against Tasmania in Hobart as they chase the win they need to hold on to second place and shore up a spot in next week's Sheffield Shield final against table-topping Victoria.
The Blues ended the penultimate day of the regular season at 5-149, a lead of 269 runs over the home side.
NSW will need to earn maximum points to avoid being leapfrogged by Western Australia.
Tasmania proved themselves to be stubborn with the bat on day three, chewing up 97.4 overs in their innings of 255 as the home side conceded a first innings deficit of 120 runs.
It could have been worse for the Blues but for pace bowler Trent Copeland (6-88) running through the tail, as the home side lost 5-23 at the end of their innings.
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NSW wicketkeeper Baxter Holt collected six catches, the second highest figure achieved on a Shield debut.
Prolific opener Alex Doolan (72), in-form Matthew Wade (34) and Ben McDermott (53) were the main contributors for Tasmania.
In reply, NSW put on a confident 81-run stand for the opening wicket between Daniel Hughes (26) and Nick Larkin (33), but soon suffered a dose of the jitters losing 4-18.
Moises Henriques hit a 69-ball knock of 49 to halt the slide, but bad light stopped play early with rain having shortened day two.
