Jantjies, 30, has played one test for South Africa in the last three years, having been a member of the 2019 World Cup-winning squad and a regular for the two years that followed.
Injury and the form of others saw him overtaken in the pecking order, but coach Rassie Erasmus has brought him back into the fold to vie with Cobus Reinach, Grant Williams and Morne van den Berg for a place in next year’s World Cup squad.
"The fire burns in me again," Jantjies told reporters. "I again feel like a young 22- or 23-year-old Herschel Jantjies.
"A lot has changed (within the team), it is incredible working with the coaches like Tony Brown and Jerry (Flannery). There have been a lot of learnings from them and seeing how they want to play the game.
"The opportunity is here now and it is time for me to show what I have learnt. Being in the squad and not playing, I still learnt a lot from the training and sitting in the team meetings."
Jantjies’ chance has come after injury to Grant Williams and a desire by Erasmus to rotate his players, making 13 changes for the one-off test against Australia.
"The competition (among) the nines in the squad is amazing. We challenge each other in a healthy sense. Grant, Krappies (Van den Berg) and Cobus are all great players.
"Each one of them has something special that they bring to the game and it is very important to me that I can learn from them and learn from the coaches.
"It doesn’t make it easier for me, but it gives me the energy to want to show the coaches and say to the team I do belong here. Hopefully I can show that on the weekend."