Victory saw the Proteas bounce back in style after they suffered a 211-run defeat in the first of a four-match series at Lord's -- a fixture du Plessis missed following the birth of his first child.
"We did the basics a lot better and put England under pressure for long periods," du Plessis told Sky Sports.
"We focused on getting back to things this side does really well," he added of a South Africa side with a proud away record of just one series loss in their 19 previous Test campaigns on the road.
Du Plessis took the bold decision to bat first after winning the toss at Trent Bridge, a ground known for aiding swing bowlers, and was rewarded with a competitive total of 335 all out.
With South Africa coach Russell Domingo missing this match following the death of his mother and the attack without fast bowler Kagiso Rabada, banned for one game as a result of swearing at England's Ben Stokes at Lord's, the Proteas then dismissed England for 205.
Du Plessis's painstaking 63, demonstrating an ability to graft for runs quite beyond most England batsmen this match, helped South Africa to a second innings total of 343 for nine declared.
That left England needing a mammoth 474 for victory -- the most made by any side to win in the fourth innings of a Test is the West Indies' 418 for seven against Australia at St John's in 2003.
England, however, collapsed to 133 all out with more than a day to spare on a pitch, which while worn was no 'minefield' and with sunny blue skies providing some of the best batting conditions of the Test.
Vernon Philander, the man-of-the-match, led South Africa's attack with three wickets for 24 runs in 10 overs of accurate fast-medium bowling.
South Africa had collapsed to 119 all out at Lord's but they were on top at Trent Bridge almost from the start and never let up.
"There were periods in the first Test when we played well but then let England dominate us," said du Plessis.
"This was an important Test for us."
The Proteas now have a nine-day break until the start of the third Test at The Oval on July 27, with no tour match in between.
But with several of South Africa's multi-format players in England since May, du Plessis reckoned a break may be no bad thing.
"A few of the guys have had a long tour -- I've just had a break so I feel mentally refreshed and strong, but I feel a couple of days off will give the guys a chance to relax and get away and in a week's time come back with the same intensity," he said.
For England this reverse again raised questions about their fallible top three, a problem for them while they lost eight Tests last year.
Keaton Jennings and current number three Gary Ballance, a longstanding team-mate of Root at Yorkshire, have made just 44 and 85 runs respectively in four innings during the series so far.
"No, I don't think it (the top three) is a concern," insisted number four Root.
"They just need some runs and to spend some time out in the middle.
"Credit has to go to South Africa, who played very well over the course of the game, but we've got to make sure this doesn't happen again," he added.
Meanwhile England coach Trevor Bayliss was adamant none of the side were trying to hide from the scale of this defeat.
"The boys are fairly honest in the changing room and realise they have had a shocker," the Australian said.
First Published: July 17, 2017, 11:40 PM IST