Ryan Brunt grabbed an injury-time winner to move the Pirates out of the League Two relegation zone after Barnet substitute Harry Crawford had equalised Fabian Broghammer's 77th-minute strike in the final minute.
Davids said: "If we had taken a point I would have been very happy because at times some of our football was unbelievable.
"We played the ball out from the back and enjoyed some really good spells but the lesson we have to learn is that you need to concentrate for every one of the 90 minutes.
"Football-wise we are definitely on the up and I see so many things to give me encouragement.
"But it is all about results and we have lost a game we should have taken something from so I cannot be happy."