Dec 4 (Reuters) - Less than two weeks after being dismissed as a "dud" Down Under, Joe Root finally shrugged the monkey off his back with a first test century in Australia on Thursday to breathe life into England's Ashes campaign.

Unbeaten on 135 from 202 balls, Root exited the Gabba with England 325 for nine at stumps on day one of the second test, having delivered the perfect riposte to his Australian critics.