The Ospreys were missing 13 key players - the likes of Gavin Henson, Brent Cockbain and Justin Marshall - but fought back from 13-3 down to win the game.
And Jones backed Wales to go on and nail a second straight Test win over Australia following last November's 24-22 victory.
He said: "I hope the result has a good affect on Wales. I am sure the win last night will have done the senior Australian side more negatives than positives in their preparations leading into the game.
"Wales can take heart that, as long as they can apply themselves, they can get a positive result on Saturday."
Australia took a 10-3 lead with a blistering try created by Cameron Shepherd and finished off by Adam Ashley-Cooper.
But the Ospreys hit back to draw level at 13-13 with a try from hooker Barry Williams after the visitors' James Holville had been sin-binned.
Fly-half Shaun Connor, named man of the match, edged the Ospreys ahead with his third penalty and a drop goal before Mustoe's grandstand finish.
If Australia were unsure what to expect from Gareth Jenkins' Wales on Saturday, they were fully briefed at the Liberty Stadium last night.
Jones said: "Australia were very physical. They really hit us hard in the first 20 minutes and we struggled to cope with some of the physicality but we stuck in there, we were resilient and took our opportunities when they came.
"In cricket, you have to go to different places and it takes different qualities to win. It is the same in rugby.
"You come to south Wales and you have to front up and appreciate the game will go all the way because no-one will lie down."
Jones declared the Ospreys win ranks alongside some of the great club triumphs over touring sides from the southern hemisphere.
Swansea - forerunners of the Ospreys in the days before Welsh rugby was split into professional regions - and Llanelli both beat world champions Australia in 1992.
"When a major touring side comes along, as high profile as Australia, and you win, it is as good as anything," said Jones, who played for Llanelli in their win over the Wallabies 14 years ago.
"It is a fantastic occasion. It is a big result. I think we have caught everybody a little bit by surprise with the effort the boys put in and they got their just rewards.
"Some of the players will never play against a team as good as Australia. I am very pleased for a lot of them to achieve something like this.
"I did it myself once upon a time and it was the most exhausting experience of my life.
"I have a lot of happy memories from that and I hope our players will pick up those memories.
"Some of the players in that changing room will never play international rugby but the gold jersey turned up last night. A lot of those fellas are playing for World Cup selection next year."