PERTH: A victory for Australia at the WACA would give them an unassailable 3-0 lead in the five-match Ashes series.
Australia have made one change to the side that won the second test, with seam bowling all-rounder Mitchell Marsh replacing out-of-form number five batsman Peter Handscomb.
England have stuck with the same team that lost by 120 runs in Adelaide but tweaked the batting order with Jonny Bairstow promoted to six and all-rounder Moeen Ali going down to seven.
Root thought the pitch might provide some assistance to the bowlers early on so it was up to his batsmen to put pressure on the hosts.
”There is a bit of live grass on it,“ Root said. ”It might do a bit. We have to focus on playing well in the first session in particular. We know how crucial first innings runs are.
”I suppose if we can get big runs, having scoreboard pressure and as the game goes on that will play into our hands.
“It’s a good chance for the guys to turnaround what was half a performance last week and into a full one.”
Smith said Handscomb was unlucky to miss out but the pitch at the WACA had titled the selection towards Marsh’s medium pacers to take some of the workload off the frontline bowlers.
“The stats here over the last couple of years have shown we have needed to bowl a lot. We want to keep the three bowlers up. We have gone with that option,” he added.
Smith added that he too would have chosen to bat had he won the toss.
“I would have batted definitely,” he said. “Usually a nice wicket. Slower today and speeds up as the game goes on.
“Hopefully we can make first use of the new ball. Might seam around. There’s a little bit of grass. Hopefully they can get something out of it.
“We are in a good position. Hopefully we can put pressure on England and try to wrap the series up here in Perth.”
The opening day of the match has been overshadowed by a British media report that underground bookmakers from India had offered to sell undercover reporters information about spot-fixing in the test.
Australia: Steve Smith (captain), David Warner, Cameron Bancroft, Usman Khawaja, Shaun Marsh, Mitchell Marsh, Tim Paine, Pat Cummins, Mitchell Starc, Josh Hazlewood, Nathan Lyon.
England: Joe Root (captain), Alastair Cook, Mark Stoneman, James Vince, Dawid Malan, Jonny Bairstow, Moeen Ali, Chris Woakes, Craig Overton, Stuart Broad, James Anderson.