Phehlukwayo, the hero of Hamilton for his late batting contribution to their victory last Sunday night, finished on 29 off 34 balls, was aiming for the fence, or to clear it.
"That's exactly how I saw it," de Villiers said.
"He had the ability to clear (the fence) twice. That was the plan. Southee bowled a fantastic over, credit him and (Trent) Boult in the last two overs.
"I thought they landed the yorkers really well, had good plans in place."
Boult and Southee bowled terrific last overs, and even though the pair conceded 123 runs from their 20 overs, they got it right when it really mattered, having both served up average overs earlier.
Legspinner Ish Sodhi was thrown the ball for the 47th over, with 37 needed and tall allrounder Dwaine Pretorius hitting cleanly and far on his way to 50 off 27 balls.
Sodhi conceded just four runs which was testament to his nerve holding in a crunchy situation.
New Zealand lost a tight finish in game one in Hamilton last Sunday, and got over the line yesterday in another thriller.
"Wins against the best team in the world aren't going to come easy," New Zealand skipper Kane Williamson said.
"To get a very competitive total on that surface was a brilliant effort.
"South Africa did bat very deep and AB (de Villiers) chases down most totals.
"And our death bowling was just superb."
That came after man of the match Ross Taylor's record-setting 17th ODI century, 102 not out off 110 balls which, in harness with Jimmy Neesham's 71 not out off 57 balls, pushed New Zealand out to 289 for four.
Taylor became the fourth New Zealander to pass 6000 ODI runs yesterday too.
Neesham's innings was timely too, staking a claim to hold the No 6 spot for the rest of the series.
New Zealand have kept the same squad for the third game of the series in Wellington on Saturday.
Opener Martin Guptill had been expected to return but is still not ready as his right hamstring is taking longer to come right than had been hoped.