Both go head to head in match number five at the Feroz Shah Kotla Stadium in Delhi on Tuesday.
Meanwhile, let us have a look at the key battles between the players which could determine the outcome of the match.
Iyer is known to be a pinch-hitter in the format, and keeping in mind Kotla's sluggish track, Harbhajan might prove to be dangerous with his lethal spin.
It would be interesting to see how Iyer handles Harbhajan.
However, his task could be cut short if Dhoni decides to use the services of Imran Tahir early, who is currently one of the deadliest spinners in the world.
Dhawan should do his homework properly, or there shall be grave consequences.
Axar Patel is one of the lanky Indian all-rounders, who mostly dominates with his spin bowling.
He would be aiming to upset the CSK batsmen once again.
However, his first real test would be up against their opening all-rounder Shane Watson, who can take on any bowling attack in the world.
Nonetheless, keeping in mind the Delhi track, Axar does have an upper hand.
Wicketkeeper-batsman Rishabh Pant has been in the news for his attacking style of play and if he is suited for India's number four spot.
While he looks to prove himself in that department, things won't be easy when he faces all-rounder Dwayne Bravo, who has sheer pace bowling.
Nevertheless, judging by how Pant played the last game, it won't be easy for Bravo either.
Kagiso Rabada is undoubtedly one of the finest pacers for South Africa in modern days.
Yet, he would be up against a tough challenge from the great Dhoni, who too has a point to prove in the tournament.
While the Kotla track is known to assist spinners, it would be interesting to see how Rabada fares with his pace, and if Dhoni can capitalize.
Love Sports news?
Subscribe to stay updated.