If you have an ordinary captain, then you lose matches even with the best players. On the other hand, if you have an intelligent captain, then you can win matches with average players. The first scenario is applicable to teams such as Mumbai Indians and Rajasthan Royals, while the latter scenario is applicable for teams such as Kolkata Knight Riders and Punjab Kings. Rohit Sharma's captaincy is not working for Mumbai Indians.
I don't think Rohit Sharma is an ordinary captain. He is as experienced as a batsman, just as experienced as a captain. Although yesterday's match was won by Mumbai Indians only due to luck. The Kolkata players became overconfident so they lost the match.