It can sometimes be confusing listening to AB de Villiers. Some days he wants to captain, some days he doesn't. Some days he wants to keep wicket, some days he doesn't. Some days he isn't sure how much longer he wants to keep playing, some days he wants to go on for as long as he can.

But it is never confusing watching AB de Villiers. Every time he walks out, he wants only one thing: runs. For the team, for himself, for the fans. De Villiers deals in runs.

For most of the last two years, he hasn't been doing that at all. Since January 2016, de Villiers has battled injury and uncertainty and when he has been available for South Africa, he has not been at his best. Even as recently as June, his future was cloudy with a chance of retirement.

South Africa had crashed out of the Champions Trophy to start a three-month tour of England on an embarrassing note. De Villiers was not staying on for the Tests that would follow and was unsure what kind of role, if any, he would play going forward. His former captain and close friend Graeme Smith wrote a column in The Independent confirming de Villiers actually wanted to walk away from the whites at some point early in the 2016-17 summer but was convinced to stay on and allowed to take a sabbatical from the longest format.

The decision was met with mixed feelings: some felt de Villiers had earned the right to rest, others that he was picking and choosing, and in all that, the team had to find a way to sort-of move on, unsure whether they were making a clean break or just treading water until he returns. All de Villiers said at the time was that he would wait for the new coach to be announced before making a decision.

Int the months before the coach was appointed, de Villiers welcomed a second son into the world, launched a coaching tips app and enjoyed his first offseason in more than a decade. When Ottis Gibson was confirmed coach, he had made his decision. He made himself available across all three formats.

"I needed a couple of months away with the family and then Ottis made contact. I had met him before he was announced coach and I knew he was a great guy. He wanted to know where I was headed with my career and I told him I wanted to get back in the side," de Villiers said.

But not as captain.

"I had a long run as a captain. I had some fantastic ups, and also quite a few lows in between. I just felt like it was enough. I wanted to enjoy the last few years of my career. I know what Faf is capable of as captain, and I think he's going to become one of the best leaders we have had in this country. We're going to give him all the support we can."

Instead, de Villiers wanted to play with the freedom that he thrives under and which Gibson seems to be willing to provide. Though he didn't reveal exactly what it was about Gibson that he liked, he hinted that having someone with good knowledge and a strong sense of direction helped. "He is quite a confident man and knows what he wants. You get the feeling we know where we are going as a team," de Villiers said.

With 19 months between now and the World Cup, Gibson's immediate task is to begin moulding the team into a unit that could challenge for the title. He understands that because of the difference in quality between the two sides, this series is not going to give him accurate feedback on whether that process has begun, so all he can ask for now is that they play as ruthlessly as possible.

On Sunday, openers Quinton de Kock and Hashim Amla answered that call when they marched South Africa to the biggest margin of victory with an unbroken stand; on Wednesday de Villiers did. His 176 is not just about the numbers. It's about the manner in which he flayed the opposition bowling, almost from the first ball.

While other batsmen had been struggling to find the boundary, de Villiers breached it at will and accelerated as his innings took shape. His first 50 runs took 34 balls and the next 50, also 34 but then he needed just 36 balls to add a further 76 runs in a late blitz that included six of his seven sixes. That he did all that without playing an international game in more than three months speaks of his quality.

"I was still nervous," de Villiers said. "It took me an over or so to remember I had a good net in Kimberley and I am in good form. I had to remind myself that I am hitting the ball well. It was great to be out there with Hashim, he has a very calming influence. I am hitting the ball as well as ever. I just spent a bit of time out there and then some of the boundaries kept flowing."

Thoughts of a double hundred were on everyone's mind but de Villiers', who insists he does not play for records. But there's reason to believe he may yet break a few more.

De Villiers appears relaxed and ready to do his bit in a big summer for South Africa, that only really kicks off early next year against the touring India and Australia. Before then, there is the small matter of finishing Bangladesh off, and the inaugural four-day day-night Test over Boxing Day, for which de Villiers is available.

Having not played a Test since January 2016 though, he does not expect that door to open as easily as the limited-overs' one did.

"If selected, I will be there but I can't accept that I am going to be in the squad. I have been out of the squad for a while and guys that have come in have done well. You don't just walk into the Test team," he said. I am going to have to work my way back. I am prepared to do the hard work."

And that much is as clear as can be.