"He's improved [his bowling] a lot over the last year or so, he's gained 10km/h," said Smith, who admitted selectors had one eye on an upcoming four-test tour of India, when they settled on the XI for the clash in Sydney.
The 27-year-old, who will play his 50th test this week, spoke with great pride about the team's turnaround, since snapping a five-test losing streak this summer.
"Things have gone pretty smoothly since then, it was a pretty difficult time," Smith said.
"Since we made a few changes and got some new guys in, I sort of felt a shift in energy and enthusiasm.
"It's come together really well. I've been really proud of the way we've played."
Australia are chasing a 3-0 whitewash at the SCG, having already wrapped up a series win with victories at the Gabba and MCG.
Australia XI: David Warner, Matt Renshaw, Usman Khawaja, Steve Smith (capt), Peter Handscomb, Hilton Cartwright, Matthew Wade, Mitchell Starc, Steve O'Keefe, Josh Hazlewood, Nathan Lyon.