Sam Vokes scored the equaliser a minute from time when he headed in a free-kick from fellow substitute Junior Stanislas after Jordan Rhodes had scored the opener after 68 minutes.
"We defended better, higher up on the pitch in the second half," said Berg. "We'd been defending those free-kicks and corners all day long fantastically well.
"I have to give credit to the back four and goalkeeper and two central midfield players - fantastic.
"We were put under pressure a little bit too many times in the first half and they saved us, made sure that we were still in the game.
"But we were giving away a few too many free-kicks in dangerous areas and towards the end it was one free-kick too many."
Blackburn have now won just one game in seven attempts but Berg feels they are improving and will pick up another victory soon.
"We were very, very close to getting a great result," he added.
"If we took a little bit better care of the ball, (had) a little bit more mental strength, then we could have won the game. But 1-1 here is not my worst result."