Martin Guptill should have been resting a strained hamstring last night.
Instead, with the opening ODI against England on the line, he limped out at the fall of the seventh New Zealand wicket to resume an innings cut short by the injury in the fifth over. Fittingly he hit the winning run with seven balls unbowled.
The three-wicket win - 259 for seven chasing England's 258 - gave a significant confidence boost to New Zealand for the rest of the ANZ international series.
Guptill returned to an emotional roar from the Seddon Park crowd with 41 needed off 25 balls. The odds favoured England.
However McCullum was in the mood for a carve up, Guptill's situation and attitude to what was needed, provided the emotional lift, and in the end it was done with some comfort.
So well did Guptill strike the ball, that he hit 24 runs off just 10 deliveries en route to 27 not out, including the winning run, followed by a hobbling leap and air punch.
His captain Brendon McCullum, with an unbeaten 69 off 61 balls had his second consecutive personal triumph on Seddon Park, after last Tuesday's T20 win, on the back of his 74 off 38 balls that night.
Guptill, taking a short single, pulled up clutching the back of his left leg. He battled on a short time before limping off. That seemed to be the end of his night.
''He was incredibly disappointed to pull up lame, but his striking ability at the end certainly helped us. I was very pleased he was able to hit the winning runs," McCullum said of Guptill's effort, and courage.
England captain Alastair Cook lamented his team throwing away a strong start to their innings.
That said, he still rated 258 a defendable target.
''It was even stevens until the last seven overs and he (McCullum) took the game away from us," Cook said.
There was other grim news on the injury front for New Zealand, with left arm quick Mitchell McClenaghan ruled out for the rest of the series. He will have an MRI scan today to assess the full extent of his injury.
He strained his side halfway through his 10th and final over, having taken four English wickets to carry on a remarkable start to his international career. His dejected trudge back to the pavilion told a sad tale.
Guptill's heroics notwithstanding, his injury might potentially have longer term connotations. He is expected to open the batting in the first test at Dunedin, starting on March 6. He will miss the game in Napier on Wednesday and is being assessed today.
The win was set up initially by the cool-headed Kane Williamson, with a compact 74, before being sent back by McCullum and run out.
McCullum had some help from brother Nathan and Andrew Ellis on the push to the line, before Guptill's memorable cameo.
England had been in good shape when they reached 190 for three over 40 overs.
However England fluffed their lines, and New Zealand stuck to the job and were rewarded in picking up the last six wickets in 37 balls for only 38 runs.
Kyle Mills was the pick of the attack, demanding in an opening six-over spell and tidy later on, while another seasoned operator James Franklin picked up three wickets.