When in-form Blackpool winger Tom Ince grabbed his fourth goal in three games with two minute gone, a fourth consecutive away victory appeared on the card for Ian Holloway's men.
However, Davies and Derby had other ideas as the hosts gained control of an end-to-end contest after the interval.
Davies evened the scores six minutes into the second period with
an excellent free-kick and another set-piece brought about Blackpool's downfall when Davies again rose unchallenged to head Ben Davies' centre past Matt Gilks.
Blackpool remain in the play-off places, but the four sides below them in fifth position have games in hand, while Nigel Clough's Rams are up to 14th.
Ben Davies came into Derby's starting line-up at the expense of Nathan Tyson, who dropped to the bench.
Holloway named an unchanged Blackpool XI for the first time since November's defeat at Leicester, but Matt Phillips and Gary Taylor-Fletcher returned from injury to take their places among the substitutes.
The visitors made an enterprising start and captain Barry Ferguson had time to drag a speculative effort wide before they took a second-minute lead.
Brett Ormerod played in full-back Stephen Crainey down the left and his cross deflected into the path of Ince, who made the most of some generous marking to fire home.
Derby sought an immediate response, with Ben Davies' quickly-taken free-kick narrowly evading Theo Robinson in the Blackpool area after seven minutes and Robinson capitalising on a slip from centre-back Danny Wilson to shoot past the post moments later.
Ince continued to prove a handful at the other end, dancing through challenges to draw a fine stop from Rams goalkeeper Frank Fielding in the 20th minute.
The game was developing an end-to-end feel and Robinson might have done better when he prodded Paul Green's inviting low cross wide at the back post.
A subsequent period of Derby pressure amounted to very little and Blackpool ended the half on the front foot as Ormerod and Kevin Phillips had efforts deflected wide.
Steven Davies stung Gilks' palms with a vicious drive when the action restarted and the forward brought Derby level in the 51st minute.
Wilson fouled Robinson 20 yards from goal and Steven Davies clinically dispatched the free-kick into the top corner.
Shortly after the hour both sides came desperately close to taking the lead.
First Fielding produced the save of the match to tip a sweetly-hit volley from Kevin Phillips over the bar, before Robinson latched on to Steven Davies' through ball and lobbed the onrushing Gilks, but Alex Baptiste got back to clear off the line.
Robinson bore down on Gilks once more courtesy of Craig Byson's lofted pass only for the Seasiders keeper to find the block on this occasion.
The winning goal arrived with 15 minutes remaining as Blackpool were once again punished for conceding a free-kick in a dangerous position.
Neal Eardley impeded substitute Tyson on the left win and Ben Davies crossed for namesake Steve to convert a free header.
Baptiste brought another superb save from Fielding with a driving run and shot, and Derby were able to hold on.