The competition, only limited to the bottom two tiered clubs in the Football League has been credited with its smooth running, with the scores locked at 1-1 no extra-time was played out and the game went straight to penalties.
It was the fourth consecutive time that the Blades have been eliminated on spot-kicks, Harry Maguire and Ryan Flynn were guilty of missing their attempts with Joe Ironside being the only taken (on the United side) to convert from 12 yards; John Fleck netted the winning kick for the Sky Blues who march onto the Semi-Final stage in the Northern Section.
United had pegged City back, David McAllister scoring for the second time this season as late as the 81st minute – cancelling out Maguire’s (58th minute) own goal. Doyle had shot at goal and seen his shot saved and rebound to the Irishman who tapped home from close range.
Blades boss Danny Wilson had made changes to his side, opting to rest four key players; defender Neill Collins and strikers Nick Blackman, Chris Porter and Shaun Miller were replaced by Richard Cresswell, John Cofie, Marcus Williams and youngster Callum McFadzean – who was making his first start since coming through the Academy.
The visitors started out brightly with Cresswell firing over the bar, and after a scrappy half-hour, Carl Baker at the other end tried his luck but failed to trouble George Long in the United goal. Darryl Westlake and Baker both tested the opposing keepers without much avail in what was a poor first half for either side.
The second half saw a brighter 45 minutes and Coventry broke the deadlock as the game drew towards the hour mark, England U-21 international Maguire was unfortunate to deflect home Steve Jennings near post cross.
Cofie, on loan from Manchester United came close to levelling the scores as United reacted quickly following that goal; his 20 yard shot was well saved by Murphy. Jennings, who played a part in taking the lead, was in the thick of it at the other end when he cleared Flynn’s centre and Matt Hill headed over a McFadzean corner.
A trio of youngsters were thrown into the fray by Wilson, Joe Ironside, Jordan Chapell and 17 year old Italian Diego De Girolamo were given a chance to shine. McAllister levelled with nine minutes remaining, knocking home after Murphy bundled Doyle’s shot.
Long prevented City from snatching a winner when he blocked David McGoldrick’s effort before keeping out Gary McSheffrey’s shot before the referee blew the final whistle.