Derby took the tie to extra time having played out a 0-0 draw at Old Trafford. United, though, broke the deadlock shortly before the break in the additional period as defender Luca Crolla inadvertently turned James Overy's ball into the box into his own net.
And United doubled their advantage two minutes after going in front as Chido Obi all-but sealed his side's spot in the next round of the competition. Max Nessling struck in the 113th minute to set up a nervy finish, but United held out to set up a last-16 meeting with Oxford.
However, the standout moment of the night came when Kai Rooney was introduced to chants of 'Rooney! Rooney!' from the stands. The 16-year-old caught the eye during a bright cameo off the bench with Wayne and Coleen watching on in the directors' box.





