Sri Lanka need 341 more runs with eight wickets in hand for a victory while chasing a stiff target of 413.
"We do well when we bat positively," said Prasad after the day's play here today.
"Maybe if we're chasing the score, we will be able to put pressure on the opposition by batting positively. We plan to bat positively from the start of the match. We need to bat positively and stay at the crease. If we do that, then we'll get the chance to win or draw.
Ajinkya Rahane scored his fourth Test hundred to take India to 370-odd runs going into tea today but they still came out to bat for another nine overs after the break to take a 400-plus overall lead, which surprised the Sri Lankans.
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"He has batted really well throughout the series. Even in the first game he did well. In this innings, he batted really well. We knew anything up to 350 is going to be a good target for any team. They thought that that's not enough. That's why they batted till 400," said Prasad.
"It's a slow track when you get to the second innings. I just tried to bowl in good areas. When the tailenders came to bat I tried a few short balls. That worked for me. Other than that I just bowled in good areas," he added.
India were able to take two wickets today before stumps, with one of them being retiring Kumar Sangakkara, who was out for just 18 runs in his last Test innings, and Prasad said it was sad that the legendary cricketer did not get enough runs.
"We had thought he would get a big score today. Unfortunately he didn't. But there was no change in the dressing room. The only change was in the cricketers' hearts. It's a very sad day, as we don't get to play with him after this," said the pacer.