Sam Curran opens at the other end and Rickelton starts his IPL debut with a flick past mid-on for a four.
A dot later, Rickelton punches the ball down the ground for another four.
A dot later, Rickelton takes a single before Jacks lofts the full ball over mid-on for a four! 13 come off the over.
Will Jacks is the new man in and Khaleel bowls another peach as Jacks plays and misses.
Jacks is off the mark with a four! Full and on the pads and Jacks flicks easily to the right of mid-wicket as four runs and a wicket come off the over.
Left-arm seamer Khaleel Ahmed opens the attack on his CSK debut while Rohit Sharma and Rickelton open the batting for Mumbai Indians.
Khaleel starts with a dot and Rohit is beaten next ball as he plays inside the line and misses.
A dot later, Ahmed strikes as Rohit flicks it straight to mid-wicket and is out for a four-ball duck.
Chennai Super Kings captain Ruturaj Gaikwad has won the toss and elected to field against Mumbai Indians in Chennai on Sunday.
Playing XIs:
Mumbai Indians: Rohit Sharma, Ryan Rickelton(w), Will Jacks, Suryakumar Yadav(c), Tilak Varma, Naman Dhir, Robin Minz, Mitchell Santner, Deepak Chahar, Trent Boult, Satyanarayana Raju
Chennai Super Kings: Ruturaj Gaikwad(c), Rachin Ravindra, Deepak Hooda, Shivam Dube, Ravindra Jadeja, Sam Curran, MS Dhoni(w), Ravichandran Ashwin, Noor Ahmad, Nathan Ellis, Khaleel Ahmed