United named an unchanged team from the side which won at Colchester United last time out, and kicked off with the Kop behind them.
After a quiet opening, United took the lead on eight minutes.
Paul Coutts was blocked in the box, and Billy Sharp blasted home the penalty.
United had the better of the chances, Sharp was thwarted by visiting goalkeeper Lawrence Vigouroux, but failed to find a second goal.
And the hosts were punished when Brandon Ormonde-Ottewill cut inside before driving home beyond George Long.
David Edgar came close to a winner but Vigouroux saved well.
“It’s another point on the board. We’ve started the game very well,” boss Nigel Adkins said.
“We had a penalty which was well dispatched by Billy Sharp and he could have scored another straight after that.
“That second goal was just elusive. We had a good pressing game but their goalkeeper’s made some really good saves.”