Pietersen was named man-of-the-match for his 110 not out which formed the basis of England's 307 for five in a match they won by a crushing 114 runs after New Zealand were bowled out for just 193.
But it was his two sixes off medium-pacer Scott Styris, where he reversed his grip and so effectively played as a left-handed batsman long before the bowler had reached the point of delivery, that were the major talking point.
Almost since Pakistan great Hanif Mohammad pioneered the reverse sweep back in the 1950s, there have been suggestions such shots should be outlawed.
And Pietersen, who has taken the stroke on a stage by lofting the ball distances most batsmen would be happy with playing in orthodox fashion, found his shots being criticised by former England captain Michael Atherton.
Now a TV commentator, Atherton said they were unfair because while the bowler had to declare which hand they were bowling with no such conditions applied to batsmen.
But Pietersen, who in a Test match two years at Edgbaston struck a similar six against Sri Lanka off-spinner Muttiah Muralitharan, dismissed former opening batsman Atherton's comments.
"It's ridiculous, it's absolutely stupid. Reverse sweeps have been part of the game since however long and I'm just fortunate enough that I can hit it a bit further," he said.
"Nobody has seen that before and that's a new shot played today and people should be saying it's the new way to go, not criticising everything that happens on a daily basis."
South Africa-born Pietersen, whose innings went some way to contradicting his own comments just a day earlier that 50-over cricket might not long survive the advent of Twenty20, said the Styris sixes weren't off-the-cuff shots.
"It's something I practise, it's something I visualise, I go through routines in the nets."
England one-day captain Paul Collingwood, whose run-a-ball 64 in front of his home crowd was his first fifty in any form of cricket this season, was at the non-striker's end when Pietersen let fly against Styris.
"To be honest I covered my eyes as soon as he turned his body around," he said. "I feel as if I've been batting left-handed for the last month as it is," Collingwood jokingly added.
"He did actually come up the wicket and tell me he'd been thinking about doing it in bed last night so the visualisation was there anyway!"
New Zealand captain Daniel Vettori said he'd no problem with Pietersen's shot-making but added that bowlers should be allowed to bowl down both sides of the pitch and not be penalised so harshly for wide.
As things stand, most deliveries even fractionally down the leg side in one-day cricket tend to be called as wides.
But there is potential for confusion as to what side is the leg-side if a batsman, like Pietersen, turns around as the bowler runs in.
"The only thing I would say about it is that if you're going to bat left-handed then I think to even it up for the bowlers you should have both sides of the wide line," Vettori said. "If a batsman wants to change it should be fair for both him and the bowler.
"Craig McMillan hit me for a massive reverse-sweep six so that's the biggest I've seen but these were cricket slogs, they were very impressive shots.
"That's why people come and watch a guy like Kevin Pietersen play because he can produce that type of performance."
England's win out them 1-0 up in the five-match series ahead of Wednesday's second match at Edgbaston and followed on from their nine-wicket hammering of New Zealand in Friday's lone Twenty20 international at Old Trafford.
Having already taken the Test campaign 2-0, England are now on course to deny New Zealand a victory in any major international this tour.
But a cautious Collingwood, reflecting on the limited overs successes, said: "They're two great wins but we've only gone 1-0 up so we're not going to get carried away."