Rest and rotation of fast bowlers has become a contentious, and much-discussed, subject in recent years. Ask Graeme Smith, South Africa's former captain, however, and he will tell you it is all modern day mumbo-jumbo that messes up a team's mojo. Little wonder that Kagiso Rabada agrees.

"Resting is when you're off," Rabada said. "When you get time off that's when you must rest. When you need to bowl is when you need to bowl, to get yourself to the highest level you can be at. There's no room for you to rest if you're not bowling well."

After his first Test at a level slightly below excellent in Port Elizabeth, where Rabada was down on pace and lacked his usual aggression, his workload has become a topic of conversation. Rabada has played every Test since January 2016 (10) and all but two ODIs (15) and one T20 (nine) but the 21-year old denied suggestions that he is fatigued. Instead, he went the other way and, much like Dale Steyn used to say, claimed that the more he bowls, the better he feels.

"I didn't feel good rhythm in Port Elizabeth at all but I've just bowled more and got better rhythm through bowling," he said.

Before the St George's Park match, Rabada was on a three-week break after the Australia tour. He was not required to play for his franchise, Lions, in the T20 tournament and he was not called on for the exhibition match between the national cricket and rugby teams. His captain, Faf du Plessis, said he believed Rabada had "had enough rest" ahead of the series and was ready to go.

Rabada's view is clear, although he would consider accepting a prescription of rest on the advice of higher-ups. "If it's recommended you have to be open-minded about it," he said. "The people that are in your area, you have to respect their opinions because they're employed for a reason. Take their advice because they know what they're talking about.

"But you have to make the choice - it's about how you feel. So you take their advice and then see what you think of it. It's a broad topic. If you're bowling well, you feel good. You don't have to bowl as much. But I guess it comes with experience, because everyone's different - knowing yourself and knowing when to rest."

Does the same thing apply to batting? With Hashim Amla struggling for fluency and form on the eve of his 100th Test, it has been suggested he could also do with a break, but Rabada was quick to defend the team's most senior batsman. "He is not a robot so he is not going to play well all the time. He is a great player so he knows what to do to get back into form. You don't do so well for so long by fluke. He knows what to do."

Firdose Moonda is ESPNcricinfo's South Africa correspondent