Both Chennai and Hyderabad finished the league stage on 18 points, but the Kane Williamson-led side got their neck ahead to the No.1 spot with a superior net run-rate and Tuesday's victor will be guaranteed a place in the final at the same venue while the loser gets a second chance in the second qualifier in Kolkata on May 25.
With 43 needing off last three overs, Du Plessis, who opened the batting, launched into Carlos Brathwaite's 18th over smashing him for 20 runs which included two sixes and two fours. They might have lost Harbhajan but CSK knows that if there is anyone who can win the game for them, it is Faf.
"Faf's innings is where experience counts", Chennai captain Mahendra Singh Dhoni said. "And right from the first game we've used different bowlers in different ways to find out who is the best bowler at the end", Dhoni said, about constantly reshuffling his team combination.
Shikhar Dhawan was clean bowled off the first ball of the game by Deepak Chahar, who finished with figures of one wicket for 31 runs.
Afghanistan legspinner Rashid Khan (2-11) brilliantly mixed up his googlies and sharp leg breaks in his four overs as he dismissed Dhoni (9) and Dwayne Bravo (7).
Chennai, attempting to make it to their seventh final in nine seasons that they have been part of T20 2018, struck another blow just past the Powerplay period. Medium-pace bowler Sandeep Sharma also got two wickets.
In addition, Kane Williamson and team had a great stint with the ball in this season but CSK was the only franchise to hammer them twice this year.
The 34-year-old Bravo got two important wickets of Shakib Al Hasan and Yusuf Pathan, who was spectacularly caught and bowled by the West Indian allrounder. "It was a decent wicket and we would have liked 20 more", he rued. He then stands in his crease and greets the very next delivery with a mighty swing of the bat, sending the ball over cow corner for a SIX. Ahead of the clash, a women's exhibition game will take place at 2 p.m. with top Indian and foreign players taking part in the contest at the Wankhede.