England, 43-3 just after noon, was 190-3 at tea at Sophia Gardens.
The in-form Root was closing in on his seventh test century and second against Australia at 93 not out, while Ballance, struggling of late, was fighting for his 59. Root was dropped off the second ball he faced, trying to jam a Mitchell Starc delivery but edging behind, where Brad Haddin gloved the ball but couldn't hold it in his dive.
This time, Root's formidable form has allowed him to fearlessly take the attack to Australia.
He's the world's leading run-scorer in tests since May last year, averaging 82 with four centuries in a dozen tests. He has almost 1,300 runs for England in all formats this year.
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The ball comes to him the size of a balloon, and he's spreading it around to all parts.
Root, on 33 at lunch, brought up his 50 off 56 balls, and survived an lbw review by the Australians on 62. He also appeared to offer a bat-pad chance on 79, but the ball looped just out of reach of Steve Smith at short leg.
By tea, he was on 93 off 110 balls. Every one of his dozen boundaries was met with R-o-o-o-t by the capacity crowd. Root's free-flowing mindset was aided by Ballance's grittiness and determination to not give away his wicket cheaply.
He was particularly troubled by a spell of severe short-ball bowling by Mitchell Johnson after lunch, but survived, and brought up his sixth half-century in his 14th test. At 59 off 146 balls, he was seven runs above his test average, and more importantly, giving England a chance to make its decision to bat first pay off.