Redbacks maintain Shield hold on Vics

South Australia have built a hefty lead on the penultimate day of their Sheffield Shield match against Victoria at Adelaide Oval.

The Redbacks ended day three at 7-203, with their first innings lead of 102 extended to 305 by the close.

Opener Henry Hunt top-scored with 57, while Test star Travis Head warmed up for next month's tour of Pakistan with a late cameo.

Head, who made a duck in the first innings, put the ball over the fence on three occasions late in the day for a quickfire 46 off 52 balls.

South Australia need a win to bolster their outside hopes of reaching the Shield final with the Redbacks unable to manage a win from their four outings before Christmas.

Spinner Jon Holland did most of the damage with 3-55, while Will Sutherland (2-39) knocked over Hunt and Test keeper Alex Carey for 15.

There was little luck for Australian cricket's unlikely new hero with Scott Boland going wicketless across his ten overs.

Victoria's position could have been far more parlous but for a counter-attacking knock earlier in the day from the always lively Nic Maddinson.

Resuming 215 runs in arrears, the Vics were on the edge at 5-151 only for Maddinson to swipe an entertaining 82 off 134 balls, including two sixes.

South Australia's three seamers all made a contribution with Brendan Doggett taking 3-72, while David Grant and Nathan McAndrew returned 3-66 and 3-60 respectively.

The final day will offer another opportunity for Test opener Marcus Harris to impress ahead of the Pakistan tour following his 58 in the first innings.