The fact that De Kock had a relatively low percentage of boundaries for a player of his natural instincts was testimony to his ability to play the situation and the conditions on a slow pitch on which the spin bowlers sent down a large number of the overs.
However, they were completely outplayed in all departments of the game and South Africa cruised to victory to take a 1-0 lead.
Batting at number three, Bavuma's excellent 98 comes after a hard month in which he was temporarily dropped from the Test side for a home series against England that South Africa lost 3-1. "We use the momentum we have gained in the past four years, the older players and the experienced people who are among the best in the world".
That is not to say that there was any lack of effort from Eoin Morgan's players, however, or to diminish the fine achievement of a South African team in significant transition.
Eoin Morgan's men had posted a competitive 258 for eight - no side had ever chased more to win here - after Joe Denly and Chris Woakes put on 91 for the seventh wicket. "Every batsman apart from Joe Denly and Chris Woakes struggled to get on".
Denly, one of just four players who played in the test series triumph, made 87 to lift England out of trouble. Bavuma and de Kock settled in for tea and supper, milking the bowling throughout and maintaining a healthy run-rate - 173 runs in 169 balls - before de Kock was knocked over trying to hoick a Joe Root pie into the Cape of Good Hope.
On his way to his 15th ODI century, de Kock passed 5,000 ODI runs. "We'll see how it goes in the near future".
"We did brilliantly well to even put what we thought was a competitive score on the board but we were never in a position to put them (Quinton de Kock and Temba Bavuma) under pressure with the ball by taking wickets consistently", said the bowler.
"Coming back from the five T20 matches we played in New Zealand (in November), I felt physically and mentally very good, so I want to continue with that".
A third ODI half-century - 11 years after his second - for Denly was registered off 72 balls and he struck the fit-again Lungi Ngidi for two sixes before falling to Beuran Hendricks in the final over, with Woakes having become Lutho Sipamla's first global victim.
De Kock had half a century ahead of him and grated Tom Curran with contempt before Bavuma sent a bad ball from debutant Matt Parkinson over the ropes.
Champions England fielded only five of the side who played in the final, while only six South Africans survived from their World Cup squad.
The second ODI will be played in Durban on Friday, with the three-match series ending in Johannesburg on Sunday.
Bavuma seemed to be cramping as he neared his ton, which he was denied after falling lbw to Chris Jordan, but an unbeaten 38 from Rassie Van Der Dussen got South Africa home.