Batt came off the bench to score Posh's late equaliser against Gordon Starchan's side at London Road on Saturday afternoon.
"Shaun had a real go in the reserves during the week and deserved the chance to go on and make a difference," Cooper said after the 2-2 draw.
"I certainly haven't seen him do anything like that before, but it was a stunning goal ruined only by the fact we now lose him for a game due to the craziest rule in football.
"I would much rather have three points than one, but it is a start from which we can attempt to move forward.
"It is all about putting little runs of results together to try and get ourselves off the bottom and away from the relegation zone."