After scoring with his first touch in international rugby, Tom Wright will again start on the wing with Marika Koroibete and Tom Banks rounding out an unchanged backline in Newcastle.
Folau Fainga'a and last Test debutant Angus Bell will again be called upon as cover in the front row, along with Brumbies skipper Allan Alaalatoa.
The versatile Rob Valetini will cover both the second and the back row with Queensland captain Liam Wright the other forward cover.
Waratahs number nine Jake Gordon returns to the matchday 23 for the first time since Auckland and is joined by young playmaker Noah Lolesio and the electric Filipo Daugunu as the replacement backs.
Wallabies coach Dave Rennie said: "After being left out in our last Test we got the reaction we expected from Scott, his preparation this week has been excellent and his experience will be invaluable against Argentina.
"As a group, we know respect is earned daily and understand the importance of backing up our last performance with another quality effort on Saturday night.
"The tournament is evenly poised and our fate is in our own hands. We saw how much passion Argentina play with in their performance last weekend and we're excited by the challenge in Newcastle."
Wallabies team to play Argentina at McDonald Jones Stadium, Newcastle on Saturday 21 November, 9.45pm NZT:
1. Scott Sio (66 Tests)
2. Brandon Paenga-Amosa (7 Tests)
3. Taniela Tupou (23 Tests)
4. Rob Simmons (104 Tests)
5. Matt Philip (7 Tests)
6. Ned Hanigan (23 Tests)
7. Michael Hooper (c) (103 Tests)
8. Harry Wilson (4 Tests)
9. Nic White (35 Tests)
10. Reece Hodge (43 Tests)
11. Marika Koroibete (32 Tests)
12. Hunter Paisami (4 Tests)
13. Jordan Petaia (6 Tests)
14. Tom Wright (1 Test)
15. Tom Banks (9 Tests)
Replacements:
16. Folau Fainga'a (14 Tests)
17. Angus Bell (1 Test)
18. Allan Alaalatoa (39 Tests)
19. Rob Valetini (2 Tests)
20. Liam Wright (4 Tests)
21. Jake Gordon (3 Tests)
22. Noah Lolesio (2 Tests)
23. Filipo Daugunu (4 Tests)