The hosts collapsed from 139 for one and were bowled out for 216 runs, which India chased down with 21.1 overs to spare.
"We were 139 for 1. Then we were 77 for nine. To lose nine wickets in 19 overs is in anyone's language unacceptable. We've got to take that on the chin as staff, as players, and that's the reality of sport," said Pothas after the heavy defeat.
A lot of batsmen erred in judgement and played false shots to effect the middle order collapse that put Lanka out of the hunt of a good total.
"I think it's been a huge help for our guys. There's obviously some that do it better. That's true in every team around the world. What we do know is that we're not going to judge the success of that particular strategy in such a short period of time.
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"The way we look at it is in longevity, is it going to make us better players on the subcontinent? I think the answer to that is undoubtedly yes. Of course you're going to get it wrong, but people nick half volleys and nick cuts," said the coach.
"Yeah, it's tough. We probably didn't read the situation well enough. Yes, there were some execution issues as well. What we always try to drive home in the changing room is if you make the right decision but don't execute, we're more than happy with that situation. Today we were a little bit more on the making the wrong decisions side unfortunately," he said.
"It swings between hurt and embarrassment. Emotionally you get angry. You get frustrated. Am I angry with the players? Absolutely not. The players work as hard as anyone can ask of them. They've been superb.
"Support staff has been out of this world. Brilliant. They work endless hours with planning and helping the boys. You can't fault anyone within that changing room. Yes, we didn't play our best cricket today. That's pretty obvious," said the coach.