Rory Burns hit his first test century to give England the chance to build a big first-innings lead over Australia as the hosts reached 267-4 at stumps on Friday in the Ashes opener.
England trail Australia by only 17 runs and has a deep batting lineup — No. 9 Chris Woakes hit a test ton against India — still to come.
Burns faced the first and last deliveries of day two, finishing on 125 not out, though Australia missed a chance to dismiss him leg before wicket by not reviewing Nathan Lyon's delivery when the batter was on 21.
Ben Stokes (38 not out) is the other batter at the crease and has an unbeaten fifth-wicket stand of 73 runs with Burns.
Root, who was playing at No. 3 instead of his preferred No. 4 slot, was the only batter out in the afternoon session. Peter Siddle reacted quickly by sticking out his right hand — with the umpire already making plans to get out of the way of Root's shot — and caught and bowled the England captain at 154-2.
Australia convinced the umpires to provide another ball and hit back in the evening session by claiming Joe Denly (18) and Jos Buttler (5) before Burns and Stokes — Man of the Match in England's winning World Cup final against New Zealand last month — came together on 194-4.
England had reached tea at 170-2 after going to lunch at 71-1.
Pacer James Pattinson took 2-54 for Australia and Siddle was the most economical bowler with 1-43 off 21 overs.
Australia scored 284 all-out Thursday when Steve Smith rescued the team with a brilliant 144 on his return to test cricket after a ban for ball-tampering. Australia had stumbled to 122-8.