New South Wales 246 & 3 for 84 (Larkin 30*, Sayers 2-33) lead South Australia 273 (Lehmann 61, Cooper 40, Copeland 6-86) by 57 runs
A six-wicket haul from New South Wales veteran Trent Copeland put their game against South Australia on a knife's edge heading into the final day at Adelaide Oval.
The Redbacks had built a platform to set up a big lead early on the third day. Daniel Sams made the early breakthrough by removing Callum Ferguson for 36. Copeland then claimed Jake Lehmann for 61.
Tom Cooper and Harry Neilsen put together a 42-run stand before Steve O'Keefe pinned Cooper lbw for 40.
Copeland then went to work, bagging the next four scalps as South Australia managed only a 27-run first-innings lead. Copeland finished with 6 for 86 from 30 overs, his 17th five-wicket haul in first-class cricket.
New South Wales reclaimed the lead but Chadd Sayers kept their progression in check, removing Daniel Hughes and Kurtis Patterson cheaply. Moises Henriques was bowled by Nick Winter for 12 to leave the game precariously placed. Nick Larkin remained 30 not out with the Blues just 57 runs in front with seven wickets in hand heading into the final day.