'It was right up there with the best feeling ever' - de Villiers

'I've never lost my love for the game' - De Villiers (1:40)

The South Africa batsman talks about his unbeaten 126 and looks back on the down period in his career (1:40)

AB de Villiers - yes, even AB de Villiers - feared for his place in the South African side. And maybe he had a point.

After almost two years out of the Test team, first with an elbow injury and then on a self-imposed sabbatical, de Villiers did not really think he could just walk straight back in, even though coach Ottis Gibson all but assured him he would. When he did, he walked back in as stand-in captain, in a four-day day-night Test against Zimbabwe because Faf du Plessis was injured, and then he walked back in as the game-changer at Newlands against India and the top run-scorer in that series, but he still didn't feel properly back. Until now.

De Villiers has scored his first hundred since his comeback and he truly feels like he belongs. "I came into this series and the previous one against India feeling like I need to play again, to make sure I keep my spot in the team. I haven't played for a while and you're always just a couple of innings away from people starting to say, 'Is he still good enough?' so those kind of things were on my mind," de Villiers said. "I was very motivated to prove to people I could still play the game , even though I've been away for a while."

This was de Villiers' first Test hundred since his century against West Indies in January 2015 at Newlands. In that time, he was inactive for almost two years and only scantly communicative about his cricketing plans so it was understandable people thought he was done. Even his closest confidantes, like former captain Graeme Smith and current captain Faf du Plessis, thought he would retire with du Plessis going as far as insisting the team had moved on, but de Villiers hadn't. Not completely. "I never lost my love for the game," he said. "I was just tired of playing. I was just flat, physically, mentally and quite a few other factors. There was just a lot that was going on in my life and I felt like I needed to breathe a little bit."

He used the time away to introspect, to play some white-ball cricket and "to reset my thoughts and all of that, and think about where i'm going with my career and the kind of things I still want to achieve." He decided to step down as ODI captain and decided to focus his goals on "being part of a successful Test team" among other things like the 2019 World Cup.

Even though his commitment to Test cricket has been questioned, he maintains it is still the pinnacle and today he proved it. "I've always seen it as the ultimate form of the game," he said. "I love playing Test cricket. It's so rewarding after five days of toil to come out on top. And even if you don't come out on top, to know you've put everything out there."

Devoting himself completely to the task is something that has become synonymous with de Villiers and was evident at St George's Park. While the rest struggled against reverse swing, de Villiers took the attack to the Australians and then enjoyed some personal glory. For the first time, he admitted he revelled in it.

"It was ten on ten. It was right up there with the best feeling ever. I was so relieved, I was very nervous in the 90s, I don't think it showed but I was telling Vern out there that I was struggling to breathe and my legs literally went numb. It's funny when a guy who has played for 13 or 14 years says that, but it's true," de Villiers said. "It really meant a lot to me to get that hundred and I was constantly reminding myself throughout the 90s that it's not about yourself. It's about contributing to the team as much as possible, that made me feel a little bit better because the minute you focus too much on individual performance, you sort of forget about the team. But it's difficult to forget about the team when you haven't scored a hundred for three years. So it meant a lot to me today."

De Villiers quickly switched back to unselfish mode and credited his lower order for allowing him time at the crease to get to his century. "They were simply amazing out there today. They took a lot of pressure off me, they're all run-scorers. They're not tailenders who just hang around out there," de Villiers said of Vernon Philander and Keshav Maharaj, with whom he shared stands of 84 and 58 respectively. "I could go out and focus on my technique, focus on what I was doing yesterday and try and get myself into the game. I never felt like I needed to score to get us somewhere."

Maharaj was particularly eager to score runs and early in his innings slogged a Nathan Lyon ball to straight to Usman Khawaja in the deep, exactly in the spot de Villiers had told him not to target. Khawaja caught the ball with his back foot outside the rope, which saved Maharaj. In the next over, Maharaj hit Lyon in the same area for a second six.

De Villiers admitted his heart was in his mouth as that played out. "I told Keshav there are two fielders on the boundary and it's the cow corner and the long-on so preferably don't hit it there in the air. If you want to, you can hit it on the ground. The very next ball he goes for it. [David] Warner and a few of the guys were actually laughing," de Villiers said. "Luckily he got away with it and a few balls later he did the same thing. He said 'Sorry AB, sorry. But he's coming over the wicket and I like it when he's over the wicket.'"

Maharaj found the rope three more times, and helped de Villiers push South Africa into a lead that could be match-winning. De Villiers did not want to touch the money too soon but hoped South Africa would not have to chase more than 150 on a wearing pitch. "I'd say no more than 150 but if it does go more than that, we can still chase it down. But in an ideal world, 150 or less would be nice," he said.

And if he can help South Africa pull off a series-levelling win, de Villiers will really be back.