But Aussie cult hero Scott Boland struck after a rain delay to keep the contest alive, removing Root for a third consecutive innings.
The contest seemed to be heading for a draw before Australian skipper Pat Cummins struck twice in an over to shift momentum back in his side's favour.
Soon after, Boland's Ashes fairy tale continued by removing Jonny Bairstow, England's last recognised batter, for 41 to put Australia on the verge of a memorable victory.
Bairstow edged a length delivery onto his front pad, and Marnus Labuschagne claimed a comfortable catch at silly point.
The hosts suddenly needed two wickets from 10 overs for victory, but England tailenders Jack Leach and Stuart Broad did well to weather the storm and survive the pace-bowling barrage coming their way.
With bad light meaning only slow bowlers were permitted to continue, Steve entered the attack. And with 13 deliveries remaining, the vice-captain claimed his first test wicket in more than five years to add one final twist.
Smith floated up a leg-spinner at Leach, and the outside edge was caught by David Warner at first slip.
That meant Australia had 12 balls to claim one more wicket for a famous victory. But tailenders Anderson and Stuart Broad survived the final two overs, meaning the Ashes series stands at 3-0 after four tests.