Pools took the lead after 70 minutes when the official awarded a penalty after striker Steve Howard was pulled back by two defenders in the penalty area.
Neil Austin converted the subsequent penalty and although Doncaster grabbed a late leveller when skipper Rob Jones scored from close range after 88 minutes, Saunders left Victoria Park furious.
"I don't know what I can say without getting into trouble, it was an unreal decision," he said. "It's a long throw, how he gives a penalty, I don't know.
"Both players are trying to win a flick-on, you look at it and tell me. Lose games by a bit of bad luck or dodgy referee decision - that's what I've told the lads. The ref has decided to help them in the game.
"Fair play to my lads, we accepted it and scored a great goal at the end. Rob Jones showed the desire he has all season to get on the end of it."