But du Plessis didn't forget the work done by his lesser known seamers, notably new ball man Chris Morris as New Zealand, ranked No 1 in this form of the game, were rolled for 107 with 5.1 overs unbowled.
The tall Morris worked up good pace and dismissed debutant Glenn Phillips and Colin Munro in consecutive deliveries.
When seamer Andile Phehlukwayo trimmed Kane Williamson and Corey Anderson in quick time, New Zealand were 55 for four and ripe for a Tahir burst.
The world's top-ranked T20 and ODI bowler didn't disappoint, snapping up five for 24 in 3.5 overs, becoming the third South African to take five wickets in a T20 innings.
Boiled down further, Tahir took five for 20 off 15 balls.
''Everyone bowled really well. Obviously the star is Imran but the seamers on that pitch were really good in the areas they bowled," du Plessis said last night.
''He's a big reason why we've had the success we have in the last 10 months. He's just become so consistent and that's a massive weapon.
''Even if teams do get off to a good start, you know the chances of him coming on and doing well is very high."
So it proved, with wrong 'uns doing for Tom Bruce and Luke Ronchi in consecutive balls and the tail having no answer.
New Zealand's star turn, Trent Boult, reckoned his team had more issues than just their bowling, as South Africa reached 185 for six.
''I don't think they had too many runs. They posted a good score. 180 is always going to put pressure on. They bowled well but we were off the mark and outplayed by a pretty good side."
Boult's figures, 4-0-8-2, are the second best by a New Zealander among those who bowled their full allotment, behind Dan Vettori's three for six against Bangladesh in Hamilton seven years ago.
Some of his bowling colleagues were too expensive. Lessons need to be absorbed quickly, with short turnarounds between games.
Boult scotched talk that the match, a one-off, didn't matter much with the main courses of the five ODIs and three tests the key focus.
''It's still a trophy, still a series against a quality side. We've played some good cricket this summer.
''We wanted to continue that reign of being unbeaten, but it leads well into the ODI series," Boult said.
The ODI series starts at Hamilton's Seddon Park on Sunday.