Digby Ioane stuns Wales with an early touchdown for the Wallabies.
Wallabies skipper Rocky Elsom was a happy man after his were able to "make amends" for last week's defeat to Scotland with a routine 33-12 win over Wales.
The Wallabies bounced back in style with tries from Digby Ioane, James Horwill, David Pocock and Tatafu Polota-Nau and 13 points from fly-half Matt Giteau.
"We wanted to make amends for the way we played last week - we had more in us than that but that's all we put on the park. It would have been a surprise if we hadn't come out hard today, I would have been very surprised by that," he said.
He added: "We'd like to think there's a lot more in us. We've learnt a few lessons on this tour and the key is to carry them forward so that we develop into a better side than we are now."
Australia coach Robbie Deans felt the previous matches on their Grand Slam tour has seen progress.
"They haven't been far away, sometimes you just need that element of luck or good management. You could see the belief kick in tonight, it was a good effort - particularly the way they denied Wales and they kept going until the end, it was a good step for us."
"We didn't play well (against Scotland), but tonight we were a little bit more direct and we got what we deserved."
Wales coach Warren Gatland conceded that the better team won on the day.
"I think they dominated us in most facets of the game," he said. "I was disappointed, we seemed to be quite flat. Once they were in control they were quite happy to play territory and they dominated the air quite well."
Beating Merthyr has boosted Carmarthen Quins hopes of reaching a top eight spot in the Principality Premiership. Quins captain Haydn Pugh is delighted with his team's progress and is determined that everyone from the Under 6s through to the senior team, enjoys the ride.
When the Wales squad were asked to nominate individuals who played a big part in their early playing days, Wales and Dragons full back and wing Hallam Amos thought of his former Monmouth School rugby coach John Bevan.
Sam Cross and Luke Treharne have been named as co-captains of the Wales Sevens side as head coach Gareth Williams names his 12-man squad to play in the first leg of the HSBC World Series in Dubai next weekend.
Bedwas head coach Steve Law and players Nicky Griffiths and Alun Rees extol the virtues of the close knit club as they prepare to host third place RGC 1404 - who are one place head of them on the Principality Premiership points table - on Saturday.
Many of the Wales squad have said Diolch (thank you) to someone who played an important part in their early playing days by nominating them to be invited to the Wales v South Africa match. One person, Gowerton Comprehensive geography teacher Mr Dean Mason was nominated by two of his former pupils, Dan Biggar and Sam Davies.
The second WRU disability rugby pilot has been delivered, this time in Caerphilly schools, culminating in a festival at the Caerphilly Centre of Sporting Excellence, Ystrad Mynach tomorrow. Plans are in place to set up a Disability Rugby Club in Newbridge to provide long-term playing opportunities.
WRU TV: Hear from inside the Wales camp as Neil Jenkins discusses this weekend's clash with South Africa and how the squad are looking to put in a strong performance to round of the 2016 Under Armour Series