Fast bowler Dale Steyn set up a series-clinching 204-run win for South Africa on the fourth day of the second and final Test against New Zealand at SuperSport Park on Tuesday, then said he was still not quite at his best after a lengthy injury lay-off.
Playing in his first Test in eight months after recovering from groin and shoulder injuries, Steyn took three wickets with his first 11 balls of the innings and finished with five for 33 as New Zealand were bowled out for 195 despite a defiant innings of 76 by Henry Nicholls.
"I'm still a long way from where I want to be," said Steyn, 33.
"There was a lot of assistance in this wicket and I put the ball in the right spots enough times to ask questions. But I want to get the pace up a bit more.
"Overs under the belt and a little more strength work and I'll eventually get there."
Steyn took his total of wickets to 416 in 84 Tests, going past Pakistan's Wasim Akram into 11th place on the world all-time list, only five behind ninth-placed Shaun Pollock, South Africa's leading wicket-taker.
But he said going past Pollock and setting records did not motivate him.
"It really doesn't bother me," he said. "I'm not going to sit on my couch when I'm 70 and go, I was the leading wicket-taker.
"I'll remember tonight, I will remember beating Australia in Australia, I will remember winning in England and hopefully I will remember winning a World Cup. I just love this game."
Stand-in captain Faf du Plessis said it had been an almost perfect Test for South Africa. "If I had written a script it would have been almost like this."
He said South Africa's plunge from top of the Test rankings to number seven - they climbed two places after Tuesday's win - had prompted some soul searching.
"We had some real good discussions and the guys took it on board," he said. "We've found our passion again."
It looked as though it would be easy for the hosts when Steyn and Vernon Philander ripped through New Zealand's top four batsmen for seven runs inside the first four overs of the innings.
But the left-handed Nicholls, playing in his sixth Test match, displayed courage and concentration in making his second Test half-century and highest score to delay South Africa's celebrations.
He found a similarly determined partner in BJ Watling, who made 32 in a two-hour, 68-run fifth wicket partnership, while Mitchell Santner, Doug Bracewell and Tim Southee all provided varying degrees of resistance.
Nicholls was last man out for 76, scored off 140 balls with 12 fours.
Williamson said that sending South Africa in after winning the toss had been based on their expectations of a well-grassed pitch.
"They played very well to get 450-plus but there was enough in the wicket to perhaps bowl them out for a below-par total," he said.
"It was a good toss to lose and unfortunately I won it. Credit does go to the way they applied themselves with the bat. Their first innings was the winning of the match."
Batting on a pitch which deteriorated more quickly than expected had been difficult.
"Steyn and Philander are world-class bowlers. Throw Rabada into the mix, who is young and extremely talented and it makes an extremely tough challenge but one that all the batters were excited to come up against. In terms of experiences there's nothing better for you as a player to move your game forward."
He singled out Nicholls. "For a young cricketer starting his career to come up against an attack like that on a tough surface is a great experience to have. He showed a lot of character."