Mahendra Singh Dhoni on Monday defended Piyush Chawla's inclusion in India's 15-man World Cup squad, saying the leg-spinner's presence provides variety to the attack.

Chawla has been a surprise inclusion in the squad, announced on Monday by the Kris Srikkanth-led selection committee in Chennai.

"It is good to have Piyush in the side as he provides that variety to the attack. He is one guy who can bat a bit. He has scored decent runs in Ranji and also while playing in county circuit. If we plan to play with five bowlers, then he can be a handy number seven or eight batsman," Dhoni said on the eve of India's third ODI against South Africa in Cape Town.

Chawla has been picked despite not playing a One-dayer since July 2008, and Dhoni was aware of that.

"I would always say that playing in first class match or IPL match and playing in the international match is different. Piyush needs that international match practice," the India skipper said.

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Names like Rohit Sharma, S Sreesanth and Ishant Sharma missed out on selection but Dhoni said that the reserve players should be in a proper frame of mind during the tournament.

"If you are in the reserve and if any batter or bowler gets injured then you are going to come in. So it is important to be in a good frame of mind," he said.

"Finally you can pick only 15 players. It is not like you will not get chance. Have a look at the players out here. They were not featuring in the original list. At the end of the day you can pick only 15 players and somebody is going to miss out. So I would say that you should do well in whenever you get to play and then wait for your chance."

Dhoni said India need to improve their fielding and focus more on bowling at the death.

"We have to improve in the fielding department. If we get one odd run out or take few outstanding catch, it can turn the course of the game. At the same time we have to put in a lot thought and work on bowling in the death overs. When we are going to play in the subcontinent, bowling in the death becomes crucial," he said.

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In Sachin Tendulkar's absence, Virat Kohli, in all likelihood, will open with Murali Vijay, with Rohit Sharma coming in at number three in Tuesday's match, Dhoni said.

"We will be looking out to give a few players an opportunity. Even otherwise we have lost quite a few players through injury. We have seven batsmen left here, so all of them will get exposure before the World Cup."

About not playing with the best XI since almost a year, Dhoni said, "It is a big blow that we are missing quite a few players from our main list. But this is not happening for the first time. In the last one year we have never played with our best 11. This has given opportunities to the youngsters.

"Some of them have grabbed them and are part of the World Cup squad. Here too, we have levelled the series and there are three more games to go. This is an opportunity for young players."

The skipper said that India's thrilling win in the last match is history and it's going to be a fresh start on Tuesday.

"Whether we win the last game or lose, I always think that each match is a fresh start. I would like to think about the problems we are facing, and how we are going to resolve those issues. We are concentrating on what we are supposed to do. I think both the teams are pretty equal. Whoever gets good start will make an impact on the game."

On the the wicket and toss, he said, "I think the ball does a bit under lights, so toss will be crucial. But honestly speaking, I don't know the exact scientific reason as why the ball does a bit under lights. It may be because of not having natural sunlight, or it could be because of sea breeze.

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"Even spinners can play a major role. If we win the toss and they have to bat second, then they might not be that affected. If we bat second, then facing their fast bowlers under lights will be a huge challenge. South African bowlers become a bit more effective if they are bowling under lights," Dhoni said.

Asked about Parthiv Patel's selection for the current series, Dhoni said, "It depends on the situation of the series. I would love to get rest from one match. But it depends on the situation."