Rovers were unlucky not to be awarded a spot kick a couple of minutes later when visiting defender Charlie Daniels brought down David Syers, while Harry Arter's solitary first-half strike sealed three points for the Cherries.
Saunders said: "I've seen it again on video and it was a blatant penalty because their lad has just pushed him in the back.
"I thought we played really well at times, but a goalkeeping error has cost us the match and these things happen sometimes.
"We were on top for long periods in the game, but they defended with a lot of resilience and we just didn't get the breaks.
"I was pleased with the performance in view of the side we put out because we had half a team missing. I'm disappointed because we wanted to bounce back after losing the last match and it's important now that we don't go on a losing run after going seven matches unbeaten."