Head coach Warren Gatland has overseen a record 11 successive Test match defeats, and another loss would mean Wales going an entire calendar year without winning a Test for the first time since 1937.
World champions South Africa, fresh from beating England, are overwhelming favourites to make it seven victories in the last eight games against Wales.
Costelow replaces Gareth Anscombe, while there are changes in Wales’ back line from the side crushed 52-20 by Australia with club teammate Blair Murray moving from wing to full-back. Dragons Rio Dyer returning on one wing and Tom Rogers on the other, with Cardiff’s Cameron Winnett dropping out of the squad.
In the forwards, Exeter’s Christ Tshiunza replaces injured Ospreys second row Adam Beard with Racing 92’s Will Rowlands adding vital experience to the youthful side.
A gulf in caps between the two teams is highlighted by the Wales match-day 23 having a total of 334 caps, whereas the Spirngboks bench alone boasts 431.
In an unchanged front row, Gareth Thomas starts at loose-head where he will once again be partnered by Archie Griffin and captain Dewi Lake at hooker.
The back-row sees Jac Morgan partnered by James Botham, with Scarlets number eight Taine Plumtree is recalled for Aaron Wainwright. Cardiff’s Ellis Bevan partners Costelow at half-back.
Gloucester lock Freddie Thomas is set to win his first cap from the replacements’ bench, which includes wing Josh Hathaway.
Speaking ahead of the match Wales head coach Warren Gatland said:
“Last week’s result hurts, and we are just as disappointed by it as the fans.
“Our focus now is on training and preparing well for our final game of this Autumn Nations Series.
“There were good elements that we can definitely build on going into Saturday, but we have to improve our accuracy.
“We know what a quality side South Africa are and the physicality they bring. This week we need to show real courage and front-up against the world champions.”
Wales XV to face Australia
Blair Murray, Tom Rogers, Max Llewellyn, Ben Thomas, Rio Dyer , Sam Costelow, Ellis Bevan
Gareth Thomas, Dewi Lake (captain), Archie Griffin, Will Rowlands, Christ Tshiunza, Liam Botham, Jac Morgan, Taine Plumtree.
Replacements:
Ryan Elias, Nicky Smith, Kieran Assiratti, Freddie Thomas, Tommy Reffell, Rhodri Williams, Eddie James, Josh Hathaway.
[Lead image: Welsh Rugby Union]
