Out of the 3 ODI double hundreds that Rohit has scored, two of them have been against Sri Lanka. SL have in recent times, been many teams' favorite punching bag. I rate his double hundred against Australia (in 2013, Bangalore) as his best innings purely because it came against.... Australia!
I still dont think Rohit Sharma is the ideal guy to open the innings in ODI's. Especially when we tour abroad. Because when conditions are tough, he eats up balls and eventually he is going to get a ball with his name on it. And by that time, the momentum of the innings is sucked up totally and India are in trouble from which they cannot get out of. But the problem is, his double hundreds unfortunately come in the way of moving him down the order.