Batting coach Vikram Rathour says having an in-form Rohit Sharma at the top of the order changes the dynamic of the India side after he made another century on day one of the third Test against South Africa.

Rohit was unbeaten on 117 and Ajinkya Rahane 83 not out when stumps were drawn due to bad light, with India on 224-3 as they bid to secure a 3-0 whitewash after being reduced to 39-3 in Ranchi on Saturday.

The selectors promoted Rohit to open for the first time in the longest format in the series against the Proteas and the 32-year-old has grasped his opportunity, making three hundreds.

Rathour has been impressed with the application Rohit has shown following his promotion and always felt there should be a place for the dangerous right-hander in all three formats.

"He is such an experienced player I don't think you needed to do anything with his technique, the only adjustment I think he had to make was his game plans," said Rathour

"In Test cricket you need to play through those tough spells and I think he's doing that really well in this series.

"If he can keep doing that, once he's set, then he is a phenomenal player - we all know that - he can really punish you. He needed to make that mental adjustment to his game plans and he's done that well. 

"I always said he's too good a player not to be playing in any format, so I think it was a good call to get him to open and with the amount of runs scored of course, I think he has settled the issue for the time being.

"Somebody with his experience and the kind of cricket he plays, if he starts coming good for you at the top of the order that changes everything for the Indian dynamic - even when you are touring."