Derby are understood to have outbid United for the now-Rams striker, Martyn Waghorn, in the summer transfer window.
And the two clubs are said to have chased yet another shared front-line target before his move to Sheffield United earlier this week.
The Sheffield Star reports that Derby, along with Millwall and another side 'competing for a top-six finish', expressed an interest in signing Gary Madine, only to be informed that Bramall Lane was the 28-year-old's preference.
And United, who have won one and lost the other of this season's league games against the Rams, will hope there is one last laugh reserved for them in the battle for promotion.
Chris Wilder's side currently occupy third position, and will be due to face Derby in the play-offs should the table remain the same in May.
Would the new Sheffield United recruit have been a good addition for Derby County?