Damian Willemse reveals how Springboks peaked at right time to win Rugby’s Greatest Rivalry series

South Africa completed a 3-1 series triumph with a 43-28 victory in Baltimore on Saturday, having initially lost 33-16 at Ellis Park and surrendered their world No 1 ranking.

The Boks responded with wins in Cape Town and Soweto before producing their strongest performance of the series in the United States.

Willemse, who returned at fullback after missing the third Test with a hamstring problem, said the turnaround was part of a deliberate strategy.

"We rotated throughout the Nations Championship where we did a lot of variations in our plays and rotational switches with players to keep us fresh," Willemse said.

"The coaches made that point clear as they wanted us to peak in games three and four, as that's where the series was decided.

"So we understand our bodies, what it takes to peak at the end of a series or a World Cup and how to lock yourself in, in terms of recovery, your sleep, nutrition and all those other things."

The opening defeat forced the Boks to address weaknesses, with Willemse crediting the coaching staff for helping the team find solutions.

"After the first Test and taking that loss, there were certain areas of our game that we had to work on," he said.

"That allowed us as a group to look internally, help each other and tighten our game and just lock in - credit to the coaching staff for coming up with plans and solutions.

"That gave us belief after that first Test, and it's massive; for a lot of the guys this is their first big series."

Willemse was particularly pleased with how the group handled the pressure in Baltimore, where New Zealand went into half-time just three points behind before threatening again after the break.

"We knew it would be a tough series. The game in Cape Town reflected that, and the one in Soweto was also really close," he said.

"Tonight we probably ran away with it a little bit, but only towards the end around the 65th or 70th minute.

"But from the start of the series to where we are now, we've built our game and got better, and that's the thing we're mostly proud of."

The 28-year-old, who already has two World Cup winners' medals and a British and Irish Lions series triumph, said the latest achievement was especially meaningful.

"Whenever you run out to represent the Springboks and you've got the Springbok on your heart, you want to go out there and make everyone proud - your teammates, your family and South Africa," he said.

"This doesn't only belong to us, it belongs to South Africa as well."

The Boks will now turn their attention to a one-off Test against Australia in Perth on September 27.