The 25-year-old Kohli, batting at the coveted number 4 position left vacant by retired batting icon Sachin Tendulkar, notched up his fifth Test century to steer the visitors to a comfortable 255 for five at close on a bouncy Wanderers track.
Ajinkya Rahane (43 batting) and skipper Mahendra Singh Dhoni (17 batting) were at the crease on an eventful opening day which saw the beleaguered Indian batting line-up giving a good account of themselves despite their only warm-up game being abandoned due to a wet outfield.
Kohli stole the thunder on the first day as he displayed wonderful counter-attacking ability with dazzling array of strokes all round the wicket after openers Shikhar Dhawan (13) and Murali Vijay (6) were dismissed cheaply by Dale Steyn (1/56) and Morne Morkel (1/27) within 15.1 overs.
Kohli, India's premier batsman, hit 18 sweetly timed boundaries in his 181-ball knock with the standout shot being a pull off the fast and furious Steyn. He played some flowing drives, played the square cut well and was severe on leg-spinner Imran Tahir, who was repeatedly pulled towards the deep mid-wicket boundary.
His shot selection was admirable as he was ready to leave a lot of deliveries but didn't forget to punish the loose balls.
In Image: Virat Kohli celebrates his century.