The flamboyant opener, who took the wind out of South Africa's sails with a double century in the first Test win, followed it up with a valiant knock of 108 today after India choose to bat first.
India were comfortably placed at 273-3 when bad light cut short the first day's play, with captain Virat Kohli set on 63* and vice-captain Ajinkya Rahane batting at 18*.
Kohli and Rahane forged a 75-run partnership for the fourth wicket and resisted South Africa's charged up pace attack amidst fading light.
After hitting a purple patch in this series so far, Agarwal said he was elated with his good form.
"The team is in a good position, winning the toss, batting first and with one batsman short, it's a good thing to make runs... 450-500 would be nice," he remarked.
"Try and get big runs in the first innings... (that) could help us in case we don't want to bat again. It could really put pressure on the South Africans."
Virat Kohli, spearheading the Indian team for the 50th time in Test cricket, reached the half-century milestone in style with a scintillating boundary off fast bowler Vernon Philander.
However, the temperamentally strong opener, Agarwal was the standout player on the first day as even after receiving a nasty hit on the helmet from a searing bouncer by the debutant Anrich Nortje, he remained unflustered and went on to smash Nortje for three delicious boundaries down to the covers just before the lunch break.
The star batsman also knitted 138 runs with Cheteshwar Pujara, who amassed 58, after the early wicket of Rohit Sharma in the first session.
Agarwal finally edged a teasing delivery by Kagiso Rabada to the slips where Faf du Plessis took a sharp catch. Kagiso stood out from his peers and ended the day with all three scalps by just giving away 48 runs in 18.1 overs.
Agarwal while reflecting on playing under varying conditions said: "There were periods where I was getting boundaries very easily, there were periods where they bowled very good line and lengths and were testing the bouncer as well."
On the other hand, Rohit, who scored two tons in his first opportunity as a Test opener in Visakhapatnam, couldn't continue along his merry way and struggled against the new cherry.
India could break the record of 10 wins on the trot that they share with Australia if they manage to clinch this ongoing three-match Test series in their own backyard.