With regular openers Rohit Sharma, Shubman Gill and KL Rahul all missing games at some point last month, Agarwal grabbed the opportunity with both hands against New Zealand and South Africa.
Resuming the post-lunch session at 83 for no loss opener Mayank Agarwal notched up his half-century. Mayank and Rahul notched up a century partnership in the 35th over of the day.
Mayank Agarwal was 46 not out and KL Rahul 29 not out as India followed its decision to bat first by progressing through the first session at SuperSport Park without losing a wicket
After making a strong comeback into the Indian Test team during the New Zealand Test series, Mayank Agarwal is set to open with his mate KL Rahul in India's tour of South Africa.
Mayank Agarwal failed in Kanpur but regained his form to score 150 and 62 in the second Test to win the 'Player of the Match' award.
Ashwin has bridged the gap with top-ranked bowler Pat Cummins after finishing with four wickets in each innings in India's 372-run victory.
Mayank Agarwal got hit on his right forearm while batting in the second innings while Shubman Gill got a cut on his right middle finger while fielding yesterday.
The lead swelled to 332 for the hosts and in these conditions, the Indians will brace up for a three-day finish to earn some rest before boarding the charter flight to Johannesburg on December 16.
The tourists still trail by 287 runs in the first innings as Siraj, who replaced injured Ishant Sharma in the team, struck early to send back Will Young for four.
Patel, a left-arm spinner, added to his tally of four wickets on the opening day to return figures of 10-119. India were all out for 325.
India vs New Zealand, 2nd Test, Day 1: Agarwal's timely century rescues India from position of bother
The dismissal of Shreyas after an 80-run stand proved to be another hiccup, but with Wriddhiman Saha giving enough support from the other end, Agarwal swiftly moved to his fourth century at home.
The Bangalore-based opener lamented that it was his misfortune that he got hit on the head during a net session in England and then there was nothing in his hands.
Shubman Gill (44 off 71 balls) looked fluent before paying for his impetuosity which led to a mini collapse as Ajaz Patel picked up Pujara and Kohli in quick succession.
The opening batter is also looking forward to the upcoming two-Test series against New Zealand, to be held at Green Park stadium in Kanpur and the iconic Wankhede stadium in Mumbai.
The Bengaluru-born player will look to make the most out of the tournament and be in contention for a spot in India's upcoming T20I series against New Zealand.