Nathan Lyon was hailed as Australia's key bowler as the team closes in on an emphatic victory in the final Ashes Test after beleaguered England unravelled on a torrid day in Sydney today. The Australians amassed a massive 303-run innings lead and then reduced the battle-weary tourists to 93 for four at the close with a day to play.Root was unbeaten on 42 at the close with Jonny Bairstow not out 17. Lyon captured the important wickets of Alastair Cook and Dawid Malan to have two for 31 at stumps. Australia called a halt to their epic first innings at 649 for seven. Shaun and Mitchell Marsh earlier became the third set of brothers to score centuries in the same innings for Australia. Mitchell Marsh was bowled by Tom Curran for 101. Shaun Marsh was run out for 156 by Stoneman's direct throw from the covers.