After a drab 90 minutes with little in the way of real goalsciring opportunities for either side, the match was decided on spot kicks.
Youngster Louie Marsh and Benie Traore both missed before skipper John Egan skied the decisive penalty to cause a cup shock at Bramall Lane, with the League One side going through in front of their very vocal support.
Here's how we rated the Sheffield United players
1. Sheffield United v Lincoln City ratings
Sheffield United took on Lincoln City in the second round of the Carabo Cup at Bramall Lane Photo: Ross Kinnaird
2. Adam Davies - 6
Picked a few crosses out of the air and made the odd comfortable stop but he wasn't really tested that much as most of Lincoln's attacking play was thwarted before it got as far as the keeper Photo: SportImage
3. Jayden Bogle
A lot of the play was coming down the left in the first half, which meant Bogle was a bit of a by-stander. Taht changed a little in the second half but after taking a kick he was replaced by Seriki on 63 minutes Photo: Simon Bellis
4. Chris Basham - 7
Fairly typical Basham-esque performance. Won everything in the air, brought the ball out from the back brilliantly at times and never looked anything less than comfortable the entire game Photo: Simon Bellis