Thomas Ince scored against his old club as Blackpool lose on the road again.
Pool found themselves behind after just three minutes when Scotland midfielder Craig Bryson saw defenders backing off and ran forward about 20 yards completely unchallenged to drill a 22-yard shot into the corner of Blackpool’s net with goalkeeper Elliot Parish bewildered by the lack of protection.
The game was being played at a leisurely pace and Blackpool’s reluctance to chase and mark should have been punished again in the 15th minute when Simon Dawkins strode through a yawning gap to hit a fierce shot from the edge of the box.
Parish plunged to his left to palm the ball clear and when former Blackpool forward Tom Ince worked into another shooting position with minimal resistance his effort was scrambled clear.
Ince fired over in the 16th minute but what looked like a stroll for Derby was almost interrupted two minutes later when sloppy marking allowed young Blackpool winger Henry Cameron to plant a header not much too high.
That stung Derby into a stunning reprisal. Full-back Ryan Shotton raided down the left as Blackpool again backed away and Ince made room to drill a beautifully precise curling left-footed shot inside the far post in the 28th minute.
It was 3-0 when Blackpool full-back Charles Dunne underhit a routine back-pass from the restart and Darren Bent accepting another gift with a firm shot for the 11th goal of his loan spell from Aston Villa.
Derby should have made it four in the 51st minute when winger Jesse Lingard streaked clear on the left to set up a great chance which Ince drove straight at Parish from close range, and the Rams were equally careless with the rebound as Lingard blazed over the bar.
Blackpool almost cashed in after 58 minutes when Shotton’s attempt to head back to goalkeeper Lee Grant fell short and Andrea Orlandi sneaked in to stab a shot that curled narrowly wide of the far post.
Normal service was resumed in the 64th minute when Shotton burst into the Blackpool box and defender Peter Clarke dragged the full-back to the ground to concede a penalty that Bent rammed in for his fifth goal in four games.
With Derby manager Steve McClaren making changes to rest key players, Blackpool escaped further punishment - small consolation for the small group of under 100 fans who had travelled from down from Lancashire.