Blues were two goals ahead, only to be pegged back by Bolton's 10 men, for whom captain Kevin Davies led the fightback with a typical all-action display.
"He (Davies) is a difficult customer," said Ridgewell. "You know it is always a difficult game against him.
"He likes a battle and you have got to try to play him as best you can. It's a difficult venue to come to and it's a point gained from the start of the day but it is disappointing.
"We were 2-0 up going into the 70th minute and we have come away with a draw. It is definitely two points dropped from that point of view.
"Going into the season you want to be unbeaten and that is a positive for us but it just feels like a defeat coming away when we should have won."