The Proteas have taken a 1-0 lead in the series, with two matches to come on Tuesday and Thursday.
"There were talks of 250 at one point and even Hash (Amla) said when he came off that he never thought we would get to 300-plus," De Villiers said of the Proteas' big first innings score of 309.
"I thought it was a great batting performance today, it was set up by the man himself with Quinton (de Kock) and Faf (du Plessis) batting around him. It shows you that we are quite dangerous with wickets in hand in the last 10 to 15 overs, it was an exceptional batting performance."
De Villiers was equally impressed with his new-look pace attack, which was well complemented by spinners Aaron Phangiso and Imran Tahir in slow and dry conditions.
"I thought we were good in the field as well," he said. “It’s easy to go into a situation where you lose your energy and focus, especially after the first 15 overs where we started well. I thought the boys stuck to their guns quite well, we kept taking wickets and stuck to our skills, it was all-round a good 100 overs for us."
Amla and Quinton de Kock have both scored four centuries in the last seven ODIs, and have established a successful partnership at the top of the order after 15 innings together.
“I think we complement each other quite well," man-of-the-match Amla said after their fourth 100-run opening stand. "He's a fun batsman to bat with and, often if he gets to a good start, I am able to play my natural game."