India skipper Mahendra Singh Dhoni on Sunday admitted that losing quick wickets was still a concern but said his team was gradually improving and will be at its best against Australia in the World Cup quarter-finals in Ahmedabad on Thursday.

India, who had lost nine wickets for just 29 runs against South Africa in their last outing, on Sunday slipped from 218 for three to 268 all out.

"It (losing wickets) is a concern. But there is a gradual improvement (from seven for 29 to seven for 50) I am sure we will be at our best in the quarters. That's the positive I will take out of this," Dhoni said after India beat West Indies by 80 runs in Chennai.

Dhoni said the turning point of the match was the wicket of opener Devon Smith, who was dismissed by pacer Zaheer Khan in the 31st over to trigger a collapse.

- Images: Female fan fare drives World Cup

"The game really changed once Zaheer gave us the breakthrough, until then Devon was batting really well. After that we could put pressure and got more wickets than we needed and seized the game in the end," Dhoni said.

On their quarter-final showdown against Australia, Dhoni said they are focusing on the preparation rather than thinking about the result.

- We will expose Australia's weaknesses: Yuvraj

"Australia are a very strong side and very expressive on the field. But it's about how we prepare. Preparation is very important and we are just thinking about that particular day and match rather than think about the result," he said.

"Being in the present is a better option that thinking of the past or worrying about the future," he added.

West Indies skipper Darren Sammy said though they lost the match, their first objective of reaching the quarter-finals have been achieved.

"We reached our first objective of reaching the knockout stage and we have to tighten our games quickly and produce our A game to beat Pakistan in the quarters," Sammy said.

The Carribean skipper also said he was happy with the bowling.

"Rampaul was really good in his first game. He bowled tremendously, our bowing game is good, something which many felt was not our strong point. But we lost seven wickets in 30 odd runs and that is a concern," he said.

West Indies had beaten Bangladesh by nine wickets after bowling out the hosts for just 58 runs and Sammy hoped that they will carry the same confidence when they play in Dhaka on Wednesday.

- World Cup coverage

"We did well against Bangladesh at Dhaka and hopefully we will have the same confidence going in there on Wednesday," he said.

Sammy also hoped that injured players Kemar Roach and Chris Gayle will be fit for the match against Pakistan.