The home side were stunned when former Rover Kevin Davies netted after just two minutes and from that point Rovers struggled to gain any momentum.
Chung-Yong Lee's quick reactions compounded Rovers' misery when the Bolton man added a second on the hour mark, and although Jordan Rhodes reduced arreas with 8 minutes to go, it was merely consolation.
"I'm disappointed with the way we started the game," said Berg to Radio Rovers.
"We were nowhere near them, they got in behind us and scored a goal but it was not the start we would have wanted.
"We had a bad start against Millwall as well, we talked about having a good start today, but we weren't able to do it and that was very very disappointing.
"After that it evened itself out but still we didn't dominate the game like we would like to do, we didn't have the passing and the movement.
"We gave them two goals today and you can't do that against any side in this league, it makes it difficult to win games.
"We made a few changes, it did help a little bit, but we weren't as fluid, as good, as we know we can be.
"I think the substitutes that came on did well, we scored a goal but Bolton deserved the win, we got close towards the end with the fighting spirit shown but it was too late."
Rovers are back in action this Sunday when they travel to take on Burnley. Fans who haven't got tickets can listen to live commentary on Rovers Player
or watch the match on the screens at Blues Bar for just £3. Purchase your tickets online at www.onerovers.co.uk