South Australia are putting up a stubborn fight in their quest to chase down Victoria's colossal victory target of 445, heading into lunch at 5-212 on the final day of their twilight Sheffield Shield clash with the Bushrangers at Adelaide Oval.

Australia A representative Tom Cooper was instrumental for the Redbacks as he looked to guide the hosts to an unlikely win, before he fell just short of a well-deserved century on 93.

The Redbacks commanding run chase has been aided by a classy contribution from under-fire Callum Ferguson (79) and current batsman at the crease, debutant Travis Head, who already has four boundaries, on 21 not out.

Head is joined by wicketkeeper Adam Crosthwaite (1 not out) with a mountain to climb after tea still requiring a further 233 runs for victory.

Victoria's day three destroyers Jayde Herrick (2-54 from 11 overs) and Andrew McDonald (1-26 from 10 including three maidens) remain the best of the bowlers.

The Redbacks resumed play half an hour earlier at 3-113 following an early finish due to rain on day three.

Up against it on the final day given Saturday's top-order collapse of 3-31, the Redbacks started relatively slow as Ferguson and Cooper struggled to build upon their 82-run partnership.

The weather looked bleak but the middle-order duo had time to reach their half-centuries before the heavens opened in an unexpected flurry after an hour, delaying play for 20 minutes.

The delay and rain-soaked conditions didn’t affect the pair as they continued to spread the ball around Adelaide Oval through a variety of textbook shots.

The patient build-up eventually came undone however through a freak catch from Victorian captain Cameron White to dismiss Ferguson short of only his second Shield century this summer.

Ferguson pushed a Will Sheridan delivery just wide of off-stump that edged to second slip where White dove full-stretched to his right to take a phenomenal one-handed catch and put an end to the Redbacks batsman's 132-run fourth wicket stand.

Inspired by their breakthrough the Bushrangers attacked the Redbacks looking for another quick dismissal.

Victorian Jon Holland (1-57 from 19) had a big shout when Cooper was on 85 for caught behind, but the umpire deemed the ball to have beaten the bat.

Holland got his man eventually when Cooper tried to turn away a leg-sliding delivery that found the edge back to Bushrangers' orthodox bowler.