While Cummins said there is no lesser desire to achieve success purely because of a young age, he recalled his own feelings of there being less pressure given how rapid his debut had been and his inexperience.

"I said this to Sam the other day; I remember as an 18-year-old I was thinking I've got a lot more leeway because I was young," Cummins said. "I almost felt like if I didn't have a great game it wasn't my fault it was the selectors' fault for picking me. It was like, they're the idiots who picked an 18-year-old. You are so young starting out your career, it's Boxing Day, it doesn't get any better than this so just enjoy the moment.

"I spent a bit of time wondering why or how I was there, how it had happened so quick. I just remember being really excited and it's similar to Sammy this week. There's a level of naivety that you just want to go out and play like you do when you are a kid in the backyard - take the game on, have fun, and not overthink it.

"That's the message to Sam. That's definitely how I felt as an 18-year-old, just really excited, and once the game started you go into game mode and it's just like any other game."

Referencing one specific memory from his Johannesburg experience, Cummins added: "In my debut I remember trying to hit Dale Steyn over his head for runs and just thought that made sense at the time, now I look back and it's like 'geez, I'd have been crucified if that hadn't come off', so I think there is some benefit in that naivety."

Konstas has had a strong support group flying into Melbourne for his debut with friends, family and his mentor Shane Watson making the trip, but Cummins sensed someone who was coping well with his dramatic rise.

"He's quite relaxed, good fun, happy to roll along with the jokes and take the mickey out of himself and others," Cummins said. "We always encourage him to be himself. He seems like he has a good head on his shoulders for a 19-year-old so we're there backing him up."

Konstas' debut will be one of two changes for Australia from the Gabba Test with Scott Boland returning on his home ground in place of the injured Josh Hazlewood. Travis Head went through a fitness test on Christmas Day having come away from Brisbane with a quad strain but Cummins said he was "fully fit."

Head has been the most successful batter in the series with 409 runs in five innings including back-to-back centuries in Adelaide and Brisbane. The next best is KL Rahul's 235 runs. He would have been a gigantic hole to fill in the batting order. "He's hitting the ball as well as I've ever seen anyone, so long may it continue," Cummins said.

Should the Melbourne Test go the distance, there will be just a three-day turnaround into the final game at the SCG on January 3 which may provide some challenges for the quicks although speaking on Christmas Eve head coach Andrew McDonald was confident Cummins and Mitchell Starc would be able to get through. With the Adelaide Test being short and Brisbane badly effect by the rain, the overall workloads have not been too high.