The tourists, who trailed the hosts by 530 runs at the start of day four in Adelaide, ended the contest on 247-6 after 90 overs.
Mitchell Johnson, who proved the tourists' chief tormentor yesterday by claiming seven wickets, picked up where he left off on day three.
Michael Carberry (14) soon followed his partner back to the pavilion in similar fashion, as the 33-year-old took on the short ball from Peter Siddle, only for Nathan Lyon to catch out the left-hander.
However, Siddle claimed his second wicket after lunch by ending Pietersen's gallant resistance at the crease to bowl him out for 53.
Ian Bell followed shortly before tea, caught out by Johnson after he clothed a Steve Smith full-toss.
Root, meanwhile, remained in play and edged toward his century after batting a four in the 62nd over to bring his contribution to 86 not out.
However, history repeated itself for the 22-year-old, as Lyon - whose delivery led to Root's dismissal on day three - executed an inside edge that deflected off the youngster's thigh and into the hands of wicket-keeper Brad Haddin, ending a 194-ball stint.