The West End Redbacks claimed a first innings lead of 27 runs on Thursday, courtesy of a fighting 61 from stand-in captain Jake Lehmann.
Tom Cooper also contributed a rapid 40 from 47 and Callum Ferguson and Harry Nielsen each made 36 to steer the Redbacks to a total of 273 after yet another rain-interrupted start at Adelaide Oval.
Blues seamer Trent Copeland notched his 300th first-class wicket amongst stellar figures of 6/86 from his 30 overs.
But South Australia’s bowlers finished the day on a high, responding in style in the final session with three key wickets before the close of play.
Swing bowler Chadd Sayers claimed his 250th first-class wicket by removing Daniel Hughes (18) caught behind and struck again to dismiss Kurtis Patterson for 12.
Nick Winter (1/29) was SA’s other wicket-taker, while Joe Mennie was at his economical best conceding nine runs from five overs.
New South Wales nightwatchman Sean Abbott (5*) and opener Nick Larkin (30*) will resume for the Blues on the final day.
Play is scheduled to begin at 10:00am at Adelaide Oval on Friday.