As New Zealand enter their final fixture of a summer that began nine months ago in August, wicketkeeper BJ Watling has cautioned against an over-reaction to their three-day defeat to South Africa in Wellington, but admitted the last match of the series could define this season.

"It's not a calamity. There's a lot of talk about the collapse and these things happen and we are obviously very disappointed but we're not going to dwell on that," Watling said. "This is a very important game coming up for us. I don't think we will judge our season on that last game. But we might on this one."

It has become something of a team mantra to talk of the Wellington woes as "one bad day," as Kane Williamson described it. They may even be able to distill it down to one bad hour.

New Zealand were 139 for 5 at tea on third day and added 16 runs to that score before losing 5 for 16 in less than six overs to set South Africa a modest 81. That four of the five wickets fell to Keshav Maharaj on the most seamer-friendly deck of the series, was of particular annoyance to selector Gavin Larsen and Watling confirmed the squad has been addressing that issue.

"It was a pretty good wicket to bat on against spin and we were probably not quite as disciplined as we would like to be," he said. "We've got to take better options and make better decisions than what we did in that last innings."

The Seddon Park surface is expected to take more turn than either University Oval - which was low and slow but not raging - or the Basin Reserve, which only offered a little something out of the rough, so New Zealand need to be even more alert. Watling, a Hamilton local, is also predicting some seam and swing.

The former will bring Vernon Philander, who took a series-winning 10 for 114 including 6 for 44 in the second innings, the last time South Africa were in Hamilton, into the game. Philander only has two wickets in the series so far and the statistics might suggest New Zealand have not had to deal with the full might of him yet, but they know that is not entirely correct.

The pressure Philander and Morne Morkel created in Wellington was key to Maharaj's success and Watling wants his team-mates to ride out the quicks better in Hamilton while not letting their guard down at the other end. "They bowled very well and put us under pressure and there were some testing spells," Watling said. We've got to get through those spells and make sure we are not slacking at the other end."

For that, New Zealand need their top six to build on starts and will want to see runs from Tom Latham and Neil Broom, who have yet to contribute, because they feel that is the only way to properly challenge a strong South African attack. "There's been some glimpses of good batting and we've talked about those starts and we need to turn them to bigger scores to really put South Africa under pressure," Watling said. "We've got to be better as a unit, all the way down to 11. We've got to build partnerships and take these guys really deep. We saw in Dunedin, that we took them deep and they felt the pressure. We had them in positions we were pretty happy with."

Watling has been one of the key men in counter-attacking in this series. His fifty in Dunedin came alongside Kane Williamson, with whom he shared an 84-run stand to help put New Zealand in a position to take a first-innings lead. Then, Watling spent almost three hours at the crease in scoring 34 in the first innings in Wellington, off 132, balls and he shared in the biggest partnership of the innings, 116 with Henry Nicholls. In the second dig, Watling partnered Jeet Raval in a sixth-wicket stand of 65, New Zealand's only stand over fifty in that innings.

His appetite for a fight may result in calls for him to bat higher up, especially as New Zealand are without Ross Taylor, who is recovering from a low-grade calf tear, but the man himself says there has been no discussion about being promoted mostly because it may affect his wicket-keeping duties. "My role has always been No.7, for the majority of my keeping days," he said. "Keeping can be quite tough and a mental drain sometimes, focusing on every ball in the field and with batting at No.7, you get a bit of a break."

South Africa use the same argument for not using Quinton de Kock higher up despite his ability to accelerate the scoring rate almost single-handedly. It's the "almost" that's important though, because de Kock can't operate without a partner and he has found a promising one in patient Temba Bavuma. Watling needs someone like that at the other end, otherwise New Zealand may find him trying to do both jobs and that could end in calamity.

"I love batting and I hate getting out. You respect each delivery as well and the South Africans bowl a lot of good balls that you've got to respect and you've got to wait a bit longer to get the balls to put away," he said. "Some days its about being aggressive and take a lot more positive options and other days you might have to soak it up a bit more."