NSW have pushed ahead of South Australia as they search for a win to close their Sheffield Shield regular season.
South Australia declared 17 runs behind NSW at 9-277 late in Friday's morning session and the Blues' second dig began well with first-class debutant Blake Nikitaras making a quality half-century.
The Blues were 2-87 at tea on day three at Adelaide's Karen Rolton Oval, holding an overall lead of 104.
Nikitaras, 21, made 56, hitting two huge sixes as he and Ryan Hackney put on 54 for the first wicket.
It has been a great debut for Nikitaras, after he also made 44 in the first innings.
Nathan McAndrew ended the opening stand with Hackney caught at short-leg for 12, but Matthew Gilkes looked composed making 14 not out.
Nikitaras went shortly before tea after a disastrous mix-up with Gilkes that saw both headed to the same end, with a direct-hit from Brendan Doggett running him out.
Gilkes and Jason Sangha (one not out) will resume after tea.
NSW dismissed SA captain Henry Hunt (109) and Harry Nielsen (63) early on day three, with tail-ender Liam Scott whacking 30 before the hosts declared in search of quick wickets.
Chris Tremain (3-51) and Trent Copeland (3-58) were NSW's best bowlers.
NSW had made 294 batting first largely thanks to stand-in skipper Sangha, who scored 142 for his highest first-class score.
With Western Australia closing in on victory against Victoria, it is near impossible for the Blues to jump into the top two before next Thursday's final even with an outright win and bonus points.