Kevin Lisbie hit a late leveller for the Lions and Jackett admitted that referee Darren Deadman did have the agreement of his linesman over the spot kick decision when Daniel Bogdanovic went down under a flimsy challenge from Paul Robinson in the box.
Jackett said: "It certainly shows how far we've come as a club when we're disappointed to come to Sheffield United and get a draw.
"You should never be disappointed with a draw away from home. My first impression was that it looked a soft penalty, but I'll stand corrected if I think any different when I view the DVD.
"The one key decision was the penalty decision and the referee was backed up by his linesman."
Source: PA
Source: PA