"We were probably quite fortunate to get as much cricket in as we did. We have to look on this game as really positive and potentially one of our best test performances of the home summer."
"New Zealand's a wonderful place to tour, today the weather was great," quipped South Africa's coach Russell Domingo.
South African skipper Faf du Plessis was magnanimous.
"Everyone would say New Zealand can count themselves very unlucky. The rain has come at a terrible time for them.
"They dominated this test and deserved to have a crack at us. It's a fair assessment to say we've been saved by the rain."
South Africa would have started 95 runs behind with five wickets standing, but two fine batsmen at the crease, aggressive wicketkeeper Quinton de Kock, whose previous two scores in the series were 91 and 90, and du Plessis, whose CV includes lion-hearted defensive performances.
"We were still very driven in making sure that we do whatever it takes to get through," du Plessis reflected.
"(But) if New Zealand got a wicket early doors it would have been tough for us to get through that."
This was a test which should be remembered for a quality performance from a side shorn of three of its best players, veteran batsman Ross Taylor and new ball pair Trent Boult and Tim Southee, by injury.
A relatively inexperienced side got the bit between the teeth and, as Williamson put it, "picked up the roles they were given and ran with it. There was a great buzz among the group, they had a good time, enjoyed themselves."
The reflection for New Zealand will be on a home summer which was marred by one bad day. That was a term which was floated more than once today, and by both skippers.
"This has been a series of what ifs," du Plessis said. "The first test (in Dunedin, the last day washed out) would have been a great finish. Today would have been very exciting.
"It's all come down to a test in Wellington where New Zealand had one bad session similar to what we had yesterday. That determines the outcome of the series. For the most part it's been 50-50."
So it ends with four wins - and that's a first for New Zealand in a home season - two draws and a loss, which came down to a poor three sessions at the Basin Reserve.
Next up is the Champions Trophy in England in June; the next test cricket will be against the West Indies, at home in November. Plenty of time for reflection.
South Africa have jumped from seventh at the start of the summer to second in test rankings; New Zealand slip one place to sixth.