Pakistan defeated Kenya comfortably in their first match of the World Cup but skipper Shahid Afridi said his side will have to play with lot more energy if they desire to beat mighty Sri Lanka in front of their home crowd on Saturday.

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Pakistan opened their World Cup campaign with a thumping 205-run win over unimpressive Kenya in group A in Hambantota but Afridi said they cannot afford to relax at any point in the tournament.

"It's a good start but we shouldn't be 100 per cent satisfied. There is a lot of work ahead of us still. Good teams are coming up but there are positive points from this match for the next games," he said at the post-match press conference.

Asked about the tough encounter against Sri Lanka in Colombo, Afridi said, "It will going to be a good game. If we bowl well, bat well, we will go with positive body language in the next game. We are ready, this game is gone, that will be a new day and new game, we will have to play with more energy.

"We know how important the next game is and Sri Lanka is the best team especially in their own conditions. We will go in with the same strength and deliver as best as we can," he said.

The 30-year-old skipper was of the view that inspite of home crowd backing Sri Lanka, both the teams have equal knowledge of the conditions.

"I think sub-continent conditions for Asian teams are equal. They will have home crowd advantage but if we put together this kind of batting partnerships and bowling in good areas, then it should be a good match. I am very confident as a captain," Afridi insisted.

Asked about Sri Lanka's positive going into Saturday's match, he added, "Home advantage will be main factor. They are playing as a unit and that is key behind their success."

"The last match Sri Lanka played their fast bowlers did really well and they have a very good team combination. They've got good new guys in the side as well. We will have to play with our full strength and to win against them we have to give more than 100 per cent effort," he said.

Afridi also said that Pakistani batsmen will have to counter the threat of Sri Lankan pacer Lasith Malinga and willy Muttiah Muralitharan if they desire to beat them.

"He (Malinga) is a very good bowler. I think he is coming back from an injury, so let's see how strong he is and how much he can adjust to the conditions.

"And he (Murali) has so much experience and knows how to use it so well. He is one of the best in the world. To add to it, in these conditions he is always very dangerous and he could probably turn it on marble," he said.

Afridi added that good positive start was imperative for Pakistan to go further in the tournament.

"Whether in batting or bowling you need a positive start always. The ball was sticking to the pitch a little, so it wasn't so easy today but we need to stick to our strengths and play positively. The start is always important and I'm confident our openers will not repeat these mistakes," the skipper said.

Even though he failed with the bat, while defending the target, Afridi returned with a five-wicket haul giving away just 16 runs.

"I am feeling good. The conditions are perfect for spinners and we are trying our best to bowl well in the middle overs especially," he said.