City failed to win the game having taken the lead through Dave Brammer's penalty after 11 minutes. A great header from 'Jelleyman' (yes, you read it right) equalised for the stags 5 minutes later, and the two teams failed to break through for the rest of open play.
For the potters, all 3 penalties were missed by Brammer, Hoefkins and Duberry whilst Mansfield managed to convert all 3 of theirs with Barker, Day and Jelleyman converting.
"The penalties were disappointing but no matter how hard you work on them in training it is not the same as with a crowd," said Boskamp.
"I do not think the extra time will affect us on Saturday (against Crystal Palace). It is up to the players to see what they can do. But if they play like that it will not be possible to win."
"We played a very bad game. We cannot find excuses and I don't want to find excuses. We can only blame ourselves, especially after taking the lead, but you need 100 per cent concentration at 1-0.
"Our feet were too slow and we never won the second ball. Mansfield were the better team and it is the correct result.
"It's now up to the players to see what they can do about it on Saturday. But if we play like this, we cannot win on Saturday."
Brammer was also disapointed after his celebrations of a contract extension were cut short with a typical cup 'banana skin' loss: "We just didn't play well, there's no excuses," he acknowledged. "It was mentioned in the dressing room about having the right attitude before the game, but it just didn't happen for us.
"We need to learn from it quick because we've got two tough games coming up over the Bank Holiday against Palace and Norwich.