Pools took the lead after 70 minutes when referee Graham Scott awarded a controversial penalty after striker Steve Howard was pulled back by two defenders in the penalty area.
Neil Austin converted the subsequent penalty, but Doncaster grabbed a late leveller when skipper Rob Jones scored from close range after 88 minutes.
"It was much-improved," Cooper said. "They looked strong at the start, but we started the second half strong. There were a lot of plus points - it's been hard saying the same thing game after game. Hopefully it's a game we can build on.
Doncaster boss Dean Saunders was furious with referee Scott's penalty decision, but Cooper offered a different viewpoint.
"It looked one for me, and they are complaining - it's a foul and they are all over Stevie. If you look at it every week it is never given for all the pulling and shoving in the box. It was brave refereeing and a well-taken penalty from Neil Austin."