Sam Konstas has come up just short of a third consecutive Sheffield Shield half-century as the star opener resumed his push for a Test recall this winter.
The 20-year-old top-scored with 44 runs off 110 balls as NSW were skittled for 202, having won the toss in their Shield clash with South Australia at the SCG.
In reply, the Redbacks went to stumps at 4-97 on Thursday, with Jason Sangha (39) and nightwatchman Brendan Doggett (0) unbeaten.
"(It's) very even, I think," said South Australia paceman Nathan McAndrew.
"Obviously tomorrow morning's going to be a pretty important hour or session for both sides."
Test wicketkeeper Alex Carey (26) fell minutes before stumps, caught high in the slips by Kurtis Patterson to cap a great afternoon's bowling from Liam Hatcher (3-10)
Hatcher had earlier snared Test hopeful Nathan McSweeney (3), who nicked off in an underwhelming first dig since the Shield's resumption.
Konstas was more fortunate, spilt in the slips by Jake Lehmann on six runs early in the day.
The right-hander weathered a collapse of 3-15 that decimated his top-order teammates before lunch.
In his 100th Shield match, No.3 Patterson (6) caught an edge to become the first man dismissed by SA's best bowler McAndrew (4-23).
Serial swashbuckler Konstas slowed right down after lunch, scoring just four runs from the last 25 balls he faced and surviving a big appeal for LBW on 44.
Soon after, he swatted at an innocuous Doggett (3-70) delivery wide of off-stump and was caught by Carey.
It followed his scores of 116 and 53 in NSW's final match before the competition went on hiatus for the Ashes.
Konstas played the most recent of his five Tests in the Caribbean last winter but remains in the selection frame given uncertainty around Australia's top order and a hectic 12 months beginning August.
BBL whizkid Joel Davies (32 runs off 30 runs) made a furious cameo before McAndrew bowled him in a NSW collapse of 3-0 on the tricky deck.
"Once we pulled our lengths back, we were able to shut the run rate down a bit more and then build pressure and took wickets from there," McAndrew said.
