New Delhi, Feb 21: India may have been impressive in their World Cup opener against Pakistan, but former pacer Ajit Agarkar feels a sterner test awaits Mahendra Singh Dhoni's side when they take on a much stronger South Africa in their second pool match tomorrow.

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"You will always get a tougher test against South Africa, no doubt. Pakistan batting and the South African batting, there is a massive difference," Agarkar, who represented India in 26 Tests and 191 ODIs in his nine-year international career, said.

"Both their batting and bowling has to work, you can't really rely on one department. You cannot win a World Cup with just one department working. Having said that they bowled really well against Pakistan. Dhoni led the team very well. They were attacking which is what you want in one-day," the former player, who analyses the World Cup on ESPNcricinfo's video show 'Match Point', told PTI.

Agarkar opined that with field restrictions on, wickets are the key and the bowlers looked very positive against Pakistan. With the batsmen rising to the challenge, Agarkar said Virat Kohli, who scored a match-winning ton against Pakistan, and Dhoni will be crucial for India once again.

"Look Virat Kohli and Mahendra Singh Dhoni are two key guys that need to perform for India to do well. They have to perform consistently through the World Cup, if they perform, the Indian batting will always look good. There will be 3-4 guys who will support them but Kohli and Dhoni need to be in form for India to do well," he said.

"Fortunately for India, Shikhar Dhawan is in a bit of form, which you need desperately at the top of the innings. Rohit (Sharma) had a really good hundred at the start of the tri-series. I mean it's probably the best I have seen him bat in a one-day game," he said.

Agarkar also opined that India will certainly match up to South Africa's world class fielding standards in the Sunday game.

"Fielding is one department that India did not slacken really in the course of this Australian summer. One of the differences between India and Pakistan that day was the fielding. I mean Pakistan dropped a few catches, while India took everything that came their way and this is a very good fielding unit and it has been for sometime. So I think on the fielding front they can certainly match South Africa," he said.

India will move from Adelaide to the Melbourne Cricket Ground, but Agarkar said the defending champions should stick to their winning combination.

"Melbourne is a bigger ground so spinners will have a bit more in their favour. And I can't imagine India changing a winning combination unless the pitch has a lot more grass on it and the fourth seamer might come in handy. Otherwise I don't see why you would want to change a winning combination that has worked for you in the previous game," he said.

India came into the 50-over showpiece on the back of a 0-2 Test loss against Australia and a winless ODI tri-series, but Agarkar feels that putting the hard yard in Australian conditions for a couple of months would have made the team battle ready.

"They had a tough Australian summer so far. Look the tri-series was quite good, I mean in the sense that it has given them confidence. Adelaide is supposed to be one of the flatter wickets in Australia and they have had a good game so you can always take that confidence forward," Agarkar said.

PTI