Proteas captain AB de Villiers hugs team-mate Andile Phehlukwayo as they win the series-opening ODI against the Black Caps.

South African skipper AB de Villiers said he and his team-mates had to conquer "the toughest conditions I've ever played in" to beat the Black Caps in Hamilton on Sunday.

The 33-year-old, who has played 212 one-day cricket internationals, 106 tests and 73 T20s, and is regarded as one of cricket's greatest batsmen, thumped the winning boundary with only one ball to spare in the first of five ODIs against New Zealand.

Batting on a wicket that had been mostly under cover for days due to constant rain, de Villiers made an unbeaten 37 off 34 balls and put on an unbroken, crucial seventh-wicket partnership with rookie Andile Phehlukwayo to deny the hosts victory at Seddon Park.

GETTY IMAGES AB de Villiers of South Africa sweeps against the spin during his crucial innings against New Zealand at Seddon Park in Hamilton.

De Villiers said the amount of spin New Zealand's Ish Sodhi and Mitchell Santner were able to get made their pursuit of 208 in 34 overs an incredibly difficult task.

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NZ Cricket Black Caps captain Kane Williamson reflects on the team's ODI loss to South Africa at Seddon Park.

"Once I batted out there, I felt it was the toughest conditions I've ever played in," de Villiers said.

"It was really, really tough, especially when we started losing wickets. The run-rate crept up and I'm just happy we crossed the line.

"I decided to stay patient and to take it as deep as we can - you never know, maybe we'd get close.

GETTY IMAGES New Zealand captain Kane Williamson can't believe he didn't pick up a wicket during South Africa's successful chase.

"Not for a second did I think it was in control."

The right-handed batsman and his left-handed all-rounder team-mate - playing his 11th ODI - put on an unbroken 54 in 7.1 overs against Sodhi, Santner and the seam and swing of Tim Southee and Trent Boult at a time when it appeared New Zealand may end South Africa's winning ODI streak which has now stretched to 12.

"It was just really slow and sharp sharp sharp turn, most of the time - which was very weird," de Villiers said.

"The first innings wasn't as tough ... It's easy to say that now after we've won the game - it would have sounded like an excuse if we'd lost - but it was definitely tougher playing in the second innings. I didn't see the ball turn that much when we bowled.

"Not to take anything away from the New Zealanders - they played a fantastic game as well.

"I thought they put us under pressure with the ball, never gave up and then the ball started talking towards the end of the game, which made it really difficult.

Opposing skipper Kane Williamson labelled the tight defeat as "pretty disappointing".

"Such a fine line - you look at a few little things and go 'coulda shoulda'.

"With the bat, it was far from perfect but we did fight hard to get to a total that I thought could've been very difficult to chase down, and it proved to do so."

Williamson described the Seddon Park wicket as "a tough surface".

"We knew if we could take a wicket, break a partnership, having to start on that surface was going to be very tough - and it was. Being under covers for such a long time - we were thankful to get a game in today.

"It did take some drying out from when we got here and obviously the spinners were not easy to face on it."

De Villiers said the performance would meet one criteria and miss another completely as preparation for the ICC Champions Trophy ODI tournament in England and Wales in June.

​"Experience wise, that's 10 out of 10 for us; to be put under pressure like that with bat in hand and to come through.

"Conditions-wise, zero out of 10 - I don't think we're going to face any wickets like that in the UK.

"I haven't played on a wicket like that anywhere away from the sub-continent. It shows that you've got to adapt quickly and really look at the conditions before you start play and get the right team out there - which we did luckily today.

"It was a great win for us, but we know the series is nowhere near done."