Senior players were counseled on who should succeed Cook and were unanimous in suggesting Root.
Root and Moeen Ali (61no off 105 balls) compounded the Proteas pain with an unbroken stand of 167 for the sixth wicket.
England opener Keaton Jennings has been saved by the inability of South Africa's bowlers to keep their foot behind the popping crease.
Root's first day as captain proved to be an example of how aggression in cricket has changed over the last 40 years or so, since the West Indies's infamous bumper barrages of 1976. Other England batsmen have started well - his three immediate predecessors, Alastair Cook, Andrew Strauss and Kevin Pietersen, also recorded centuries in their first Tests as England captain - and that has been no guarantee of future success.
The day's play had reached a critical stage as England posted their 200 followed by Root's century (150 balls, 15 fours).
Philander took his wickets with breathless efficiency‚ striking in the fourth over of the match when Alastair Cook prodded a catch to Quinton de Kock.
Stokes finally provided some long-lasting company for Root, his half-century adding a growing sense of respectability to the home side's scorecard. But as he removed his helmet and led the players from the pitch in front of a scoreboard that showed England in total charge, it would be a surprise if there had been even a cigarette paper's width between his dreams the evening before and reality. And for the left-arm Dawson's first Test on home soil.
In a video on HindustanTimes.com, Hussain said that the absence of De Villiers is a "big loss" for South Africa.
White ball specialist Hales, fresh from his unbeaten 187 in Nottinghamshire's One Day Cup final triumph on Saturday, is convinced his England team-mate will thrive with the additional responsibility.
I think Joe Root as captain has had a little impact on picking Ballance, but not much as it is completely on merit. The partnership between Root and Stokes was fantastic.
That, if not quite carnage, then certainly damage, could have been a lot worse for the hosts, Root's England playing the aggressive cricket that seems the norm these days.
"He batted like Joe Root and that is the most important thing". If he can find form, Gary Ballance can do it, too.
"You can see the way he's bowling in the nets".
"I don't like the fact he is batting at three. I would have preferred him at five".
"When you get a life early, sometimes you feel like it is your day and you've got to try to make the most of it".
About 27-year-old left-hander Gary "In terms of Gary I look at how he has performed this year and the number of runs he has scored and he has been phenomenal". Root's told the reporters on Wednesday that "I'm very excited". Their lines were a pit too straight and both batsmen cashed in with most of the boundaries coming through the leg-side. It's costly for us.
"Take nothing away from Joe Root - he rotated the strike really well - but the quality of this team is that we will come back and fight".