A last minute screamer from skipper Carlos Edwards saw Town take all three points at Pride Park, beating Derby 1-0.
Scott Loach had earlier saved a first-half penalty from Rams striker Jamie Ward, before Edwards struck in injury time to win it for Blues.
Mick McCarthy made five changes to the side that faced Millwall, with Edwards, Andy Drury, Jay Tabb, David McGoldrick and Daryl Murphy all returning to the starting line-up.
Lee Martin missed out on a place in the squad altogether through illness.
Blues made a bright opening to the game and Luke Chambers came close to breaking the deadlock after 12 minutes, rising high to meet an Aaron Cresswell corner but directing his header wide of the target.
Five minutes later and Scott Loach was called into action for the first time, beating away a curling effort from Jamie Ward.
The Town stopper then got down low to superbly tip a Craig Bryson drive around the post and behind for a corner after 28 minutes.
The hosts then were presented with a great chance to open the scoring, as a Tommy Smith clearance ricocheted off Bryson and into the path of Conor Sammon but the striker failed to keep his composure and saw his effort bounce back off the post and away from danger.
Town responded immediately and seconds later McGoldrick cut inside of his marker before unleashing an effort that Frank Fielding did well to hold on to.
The game was beginning to open up and midfielder Bryson was unlucky to see an effort curl over the top of Loach’s bar.
A minute later and a surging run from Carlos Edwards saw the skipper glide past Craig Forsyth before firing the ball across the face of goal with no one in a Blue shirt able to apply a finishing touch.
Shortly after, good work from McGoldrick and Drury saw the latter find Luke Hyam in the area but the midfielder dragged his shot wide of the target.
Sammon was proving to be a real handful for the Town defenders and the Republic of Ireland international went close with a flicked header that looped just over the bar.
A minute before half-time and the game’s first major talking point arrived, as the referee awarded Derby a penalty after Smith was alleged to have pushed Richard Keogh at the back-post.
Ward stepped up to take the spot-kick but he couldn’t a way past Loach, who kept out the effort with his legs to ensure the game remained goalless at the break.
The Rams thought they had broken the deadlock after 62 minutes, as Chris Martin slotted home Sammon’s centre, but their joy was short-lived as the linesman had his flag raised to signal offside and the goal was chalked off.
Blues went close at the other end soon after, with McGoldrick spinning away from Bryson and Jake Buxton in the middle of the pitch before eventually seeing his effort charged down by Richard Keogh, with Tabb seeing his follow up effort go just wide.
At the other end, Buxton was inches away from finding the corner of the net after meeting a Paul Coutts corner but Loach was confident enough to watch the ball sail wide.
The hosts were beginning to apply the pressure and Loach did well to palm away a Jeff Hendrick shot from the edge of the area before Ward then headed wide of the target after 79 minutes.
Town almost grabbed a sensational winner with two minutes remaining, as substitute Michael Chopra teed up Cresswell but the left-back’s volley whistled just over the bar with Fielding well beaten.
Blues went close again in injury time, as Tabb dived in at the back-post but was just unable to connect with Hyam’s right-wing cross and Derby were able to scramble the ball away.
But there was still time for a late show from Town, with Edwards picking the ball up deep in the Derby half before running at the Rams defence at unleashing a screamer that flew into the far corner to win it for Blues.