Opener Rohit became the first batsman to hit five centuries in a single World Cup and is the tournament's leading scorer with 647 runs heading into the knockout stages.
Kohli, the world's top-ranked ODI batsman, has strung together five consecutive fifties but is yet to register a hundred, something he attributed his new role as the team's middle-overs anchor.
"It's been a different kind of role I have played in this World Cup," Kohli told reporters at Old Trafford.
"It's great that Rohit has been scoring so consistently, which means that coming in the later half of the innings, you have to play a different role, which is controlling the middle overs and letting guys like Hardik (Pandya), Kedar (Jadhav), MS (Dhoni) and Rishabh (Pant) express themselves.
"I've understood that roles can vary a lot in one day cricket depending on the time you step in to bat and I've been very happy holding one end and letting other guys express themselves striking at 150-160 and even 200."
PERSONAL MILESTONES
Personal milestones are the last things on the mind of the captain who is leading India's bid for a third World Cup title.
"Rohit said the same thing the other day, that he's trying to do the best for the team. In that process special things happen," Kohli said.
"I'm very happy for him and hope he gets two more (centuries) so we can win two more games," said Kohli, terming his deputy as the best one-day cricketer at the moment.
Tuesday's game will be a repeat of the semi-finals of the 2008 ICC Under-19 World Cup in which a Kohli-led India defeated a Kane Williamson-captained New Zealand in Kuala Lumpur.
"When we meet tomorrow, I'm going to remind him," Kohli said with a smile.
"Quite a nice thing to realise that after 11 years we are captaining our respective nations again in senior World Cup."
Kohli said he knew Williamson, also New Zealand's batting mainstay, was a special talent when he first saw him play in 2007.
"In an Under-19 test match, he played a shot off one of our fast bowlers off the back foot. I remember fielding in the slips and telling someone that I have never seen someone playing a shot like that.
"We always knew he had the special ability to go all the way. Now he's controlling the tempo of the game for NZ in every game he plays."
Kohli expects Williamson, New Zealand's leading scorer in the tournament, to play a similar role on Tuesday and identified him and Ross Taylor as the key wickets for his bowlers.
"He is always been the main guy for them, along with Ross (Taylor)," Kohli said.
"From our point of view, getting them early will be crucial because we know how strong they can be together in a partnership."
