Substitute Ben Davies looked to have sparked the Rams’ revival at Bloomfield Road, as the midfielder came off the bench to equalise in his 350th Football League appearance, only for Ludovic Sylvestre to seal all three points for the home side in stoppage time.
The 31-year-old took just three minutes to send a precise looping volley beyond Matt Gilks from inside the penalty area – cancelling out Gary Taylor-Fletcher’s 18th minute opener.
However, Sylvestre produced a fine volley of his own in time added on, as the central midfielder beat Adam Legzdins with a superb strike from the edge of the penalty area.
On a difficult pitch, drenched in sunshine, the Rams retained possession well in the opening stages, with Will Hughes in particular seemingly unnerved by the conditions as he sprayed passes across the midfield.
However, the Rams’ away form this season has been their downfall in their chase for the Play-Offs, and after Thomas Ince had waltzed his way through the defence and shot wide, Blackpool’s following opportunity yielded a seemingly crucial goal in their quest for survival.
After 18 minutes, Aston Villa loanee Nathan Delfouneso teed up Matt Phillips who had an effort hacked off the line by John Brayford, but Taylor-Fletcher was on hand to tap in the loose ball and put the hosts ahead.
Despite the set-back, the Rams persisted with some fluent football, as neat interplay led to Chris Martin firing a half-volley narrowly wide following Brayford’s low cross, in between two efforts from Jamie Ward, which swerved over and wide respectively.
Shortly after the half-an-hour mark, Taylor-Fletcher almost had an assist to his name, when the experienced forward tumbled over the leg of Craig Bryson in the penalty area.
After initially ignoring the striker’s plea for a penalty, referee Gavin Ward pointed to the spot after his assistant indicated there had been a foul – to the disbelief of the Rams’ players and supporters.
Ince, like at Pride Park earlier in the campaign, took responsibility, but unlike his goalscoring exploits in the reverse fixture, the exciting winger struck the inside of the post.
In the second-half, Legzdins’ finger tips denied Stephen Crainey a superb goal, as the former Burton Albion shot-stopper scampered across his line to tip the defender’s 25-yard free-kick over the crossbar.
Then for the second time in the game, Brayford displayed goal line heroics as he raced back to clear Taylor-Fletcher’s toe poke, after the striker had got the better of Keogh and Legzdins.
Substitute Davies almost had an instant impact on proceedings when his teasing cross was headed into the side netting by Jake Buxton at the far post, but the midfielder’s second and third touches of the game proved more telling.
The former Notts County midfielder followed up Jeff Hendrick’s blocked shot with neat control and a looping volley, which in slow motion, dropped into the net beyond the despairing dive of Gilks.
The goal settled the Rams, who, roared on by the visiting supporters went in search of a winner, with Ward persistently troubling Kirk Broadfoot down the left, but both Martin and Hendrick had efforts blocked following the Northern Irish forward’s subsequent deliveries.
However, despite the Rams’ dominance in the host’s final third, Delfonouso almost sealed the three points for the Tangerines when the striker’s deft back-heel lacked power, allowing Legzdins a split second to readjust and fall on the ball - to the Rams’ relief.
The away side finished nervously, and in stoppage time Davies thwarted Chris Basham’s goalbound effort, but the Rams’ failure to clear the ball was punished when Sylvestre sent a half-volley beyond Legzdins in the final seconds, to ensure Blackpool’s survival in the npower Championship.
Blackpool: Gilks; Broadfoot, MacKenzie, Cathcart, Crainey; Ince, Sylvestre, Ferguson, Ince; Tayor-Fletcher (Basham 66), Delfouneso.
Subs not used: Halstead, Eardley, Grandin, Angel, Derbyshire, Eccleston.
Derby County: Legzdins; Brayford, Keogh, Buxton, Forsyth; Hendrick, Bryson, Hughes (Freeman 75); Ward (Jacobs 83), Sammon (Davies 62), Martin.
Subs not used: Deeney, Bennett, Roberts, Doyle.
Attendance: 14,775 (1,657 visiting supporters).