The wicketkeeper-batsman struck 100 from 84 balls against Sri Lanka in their opener and followed that up with 109 from 106 versus Australia on Thursday to help his side to two thumping wins at the start of a campaign where many had written them off.
"It was a great win for the boys, we assessed conditions well and played accordingly, stuck to our strengths and came out on top," De Kock said.
"They (the Australian bowlers) were potent up front, so we assessed our scoring options. We are pretty pleased with ourselves, but we are only two games in and anything can happen."
He retired from test cricket two years ago and will bow out of ODIs next month to focus on the lucrative global Twenty20 circuits, a format where he will remain eligible for South Africa with a T20 World Cup looming next year.
"I find it quite tiring," he said of ODI cricket this week.
"I think I'm pretty much the same whether retired or not retired. It's just a matter of working on one or two things and going out there and getting it done."
De Kock, who has scored 19 centuries in 147 ODI innings, said there was no secret behind his last two at the World Cup.
"I've just been working on one or two things in the Australian series (last month in South Africa) and now here in our preparations," he added.
South Africa will face the Netherlands in their third match at the World Cup in Dharamsala on Tuesday.