Chennai: Afghanistan mystery spinner Noor Ahmad excelled on his Chennai Super Kings debut before skipper Ruturaj Gaikwad struck a sublime fifty to set up a four-wicket win over their biggest rival Mumbai Indians, in the Indian Premier League here on Sunday. Ahmads four-wicket haul limited Mumbai Indians to a below-par 155/9 after the hosts put them in to bat on a slow surface. Gaikwad, batting at number three instead of opening alongside Rachin Ravindra, smashed 53 off 26 balls before the