Darren Ferguson admitted he felt a great deal of frustration as familiar issues saw Rovers beaten by neighbours Scunthorpe United.
Lee Novak's first half header from a corner was enough to separate the two sides in a tight derby clash at the Keepmoat.
Disappointed with poor marking at the set-piece, Ferguson also criticised the concentration John Marquis and Andy Williams showed with two excellent chances early in the second half as Rovers slipped to a sixth league game without victory.
"Like many other games this season it was very frustration and it was another game we felt we should have taken something out of but we haven't done," Ferguson said.
"It's a disappointing day for us and for the fans because you don't like to lose derby matches.
"The word I used with the players is concentration.
"I keep using it. I keep saying it to the players and trying to drum it in.
"That's why the players at the top play at the top.
"Concentration from a set-piece, concentration in chances - clear and easy chances.
"They are the fine lines between winning and losing games and they are the things that are costing us at the moment.
"You lose a man for a set-piece and then with two excellent chances in the second half we should be 2-1 up ten minutes into the second half.
"It wasn't a bad performance and we certainly shouldn't have lost.
"We have to find a way of winning these games because fine lines are costing us."
Ferguson revealed Tommy Rowe - who was expected to be out for a fortnight - declared himself fit to play late in the week.
And Jordan Houghton missed the game through illness.