At stumps on the third day, England stood at an imposing 389-9 in their second innings, holding a commanding lead of 377 runs against Australia.
Root, displaying sublime form, scored 91 runs, while Bairstow added a brilliant 78 runs during their partnership of 110 for the fifth wicket. The only disappointment for the home crowd was that neither Yorkshireman could complete an individual century.
Although Mitchell Starc‘s impressive performance (4-94) resulted in a late flurry of wickets, England’s top order had already done significant damage, giving them a strong advantage.
The spectators erupted with joy when last man James Anderson contributed with the bat, reverse sweeping Todd Murphy for four and then conventionally sweeping the off-spinner for another boundary.
Australia, facing a challenging target, would need to achieve one of the highest fourth-innings totals in Test cricket history to pull off an improbable victory. As the day progressed, England remained in a dominant position, thanks to Zak Crawley’s fine knock of 73 and Harry Brook’s contribution.
Bairstow, known for his aggressive approach, continued to maintain the run-rate, scoring 34 runs off just 35 balls by tea, with England at 265-4. Bairstow reached his half-century with an emphatic cover-drive off Josh Hazlewood.
Root, who was unbeaten on 61 at tea, elegantly drove the ball to the cover boundary off Australia’s captain Pat Cummins, moving into the 90s. However, he narrowly missed out on another century in the series, being dismissed for 91 when a Murphy off-break kept low and breached his defense between bat and pad.
Despite Root’s missed century opportunity, England’s substantial lead ensured their strong position in the Test match, and Australia faced an uphill battle to pull off a miraculous victory in the remaining innings.
Bairstow, fresh fresh from his blistering 99 not out in last week’s rain-marred drawn fourth Test at Old Trafford, also fell short of three figures when he flat-footedly cut at left-arm fast bowler Starc and was caught behind.
Earlier, England needed only one over to erase their 12-run first-innings deficit at the start of play on Saturday.
Crawley, who had struck a cover-drive for four off the first ball of the series, repeated the shot off the first ball on Saturday before left-hander Ben Duckett ended the over with successive boundaries.
But an opening stand of 79 ended when Duckett, on 42, edged a full-length Starc delivery to wicketkeeper Alex Carey.
Crawley, the leading run-scorer in the series, took England to 130-1 at lunch.
England captain Ben Stokes, who had promoted himself up the order, with Moeen ruled out of batting in his number three position after being off the field all day Friday with a groin injury, ensured the runs kept coming
Stokes hooked Hazlewood for six in the first over after lunch, with Starc dropping a catch on the fine leg boundary.
Crawley added just two runs to his lunch score of 71 when he edged Australia captain Pat Cummins to Steve Smith at second slip, with England now 140-2.
Root then demonstrated the range of his strokeplay by reverse-scooping Mitchell Marsh for a superbly timed six and next ball gliding the all-rounder down the legside for four.
The former England captain then drove Starc down the ground for four, with even his mishits going for boundaries — next ball an under-edged cut bounced over Carey’s head.
But there was nothing lucky about Root’s third four in as many balls off Starc, a deliberate uppercut.
Stokes, gave his wicket away on 42 when caught at mid-on off a mistimed drive against Murphy.
Australia, as the holders, have already retained the Ashes at 2-1 up.
But they must avoid defeat at The Oval if they are to win their first Ashes series in England since 2001.
(With AFP inputs)