Mahendra Singh Dhoni rolled back the years with an unbeaten 38-ball 50 but his team Chennai Super Kings went down to Kolkata Knight Riders by six wickets in the Indian Premier League (IPL) opener on Saturday. The 40-year-old Dhoni, who passed on the captaincy to Ravindra Jadeja on Thursday, lifted holders Chennai from a precarious 61-5 to post 131-5 after being put into bat in Mumbai. Kolkata reached their target in 18.3 overs with new skipper Shreyas Iyer unbeaten on 20 at the start of the Indian Premier League. Ajinkya Rahane top-scored with 44.