SUPER-SUB Kevin Phillips turned the game on its head with a quickfire late double to seal an unlikely victory and send the Baggies back to the top.
Ben Burgess headed Pool in front in the 35th minute as Albion's Achilles heel of conceding from set-pieces once again reared its ugly head.
The visitors failed to convert long spells of possession into goalscoring chances and were on course for their first defeat in six on the road until Phillips converted Albion's 100th goal of the season from the spot in the 81st minute.
The former England man then tapped home his 24th goal of the season three minutes later to send the 1,642 travelling fans into raptures.
And Ishmael Miller completed a remarkable comeback by adding a stylish third in the 87th minute - his 16th goal of the campaign - as the Baggies became the first side to beat the Seasiders on their own patch in 2008.
The last-gasp win was enough to propel Albion above leaders Bristol City on goal difference.
Luke Moore earned an instant recall to Tony Mowbray's starting XI after a four-game absence.
The boss also made three other changes as he adopted a 4-3-3 formation at Bloomfield Road, with Miller, Chris Brunt and Pele elevated from the bench.
The men to make way were Phillips, Roman Bednar and James Morrison, who were relegated to the dugout, while Zoltan Gera was rested altogether.
After an uneventful start, the first effort on goal finally materialised in the 11th minute when Neil Clement headed Brunt's inswinging, right-wing free-kick wide of the near post.
But just two minutes later, Albion had a real let-off when Burgess headed Stephen Crainey's free-kick against the underside of the crossbar, with Kiely's finger-tips possibly helping it on its way.
Shaun Barker latched onto the rebound but his goalbound strike was blocked by Clement for a corner.
The Baggies broke well out of defence in the 16th minute when Carl Hoefkens' raking pass sent Miller in one-on-one with full-back Crainey.
But the ex-Manchester City striker could only earn a corner after failing to look to his right where Brunt would have had a free sight of goal.
In the 25th minute, Brunt tried his luck with a dipping 30-yard volley which landed on the top of the net, with keeper Paul Rachubka looking worried as it flew over his head.
Albion almost shot themselves in the foot 60 seconds later when Clement conceded possession to Wes Hoolahan who slotted Stephen McPhee through on goal, only for the pint-sized striker to fire wide of the right-hand post.
The Baggies were forced into a change in the 28th minute when Albrechtsen limped out of the action clutching his groin and was replaced by Leon Barnett.
Brunt fed Miller down the left on the half-hour mark and he flashed a low ball across the six-yard box which Moore came within inches of getting a telling touch to.
All the play was heading in one direction but the Baggies fell behind in the 35th minute when Burgess stole in to head home Crainey's right-wing free-kick from six yards.
Just a minute later, McPhee beat the offside trap but fortunately Barnett and Kiely did enough to force him wide and block his effort.
From the resulting corner, the ball found its way through to Gary Taylor-Fletcher at the back post.
The Seasiders' winger slid it into Kaspars Gorkss who swiveled to fire in a low left-foot shot which deflected off an Albion defender and crept inches wide of the far post.
Five minutes before the break, centre-half Ian Evatt let fly with a speculative 35-yard effort which beat Kiely and dipped inches over the bar.
Mowbray switched to a 4-4-2 formation at half-time, with James Morrison coming on for Pele.
But it was the Tangerines who started the second period more brightly.
And a swift break gave McPhee the chance to square across the 18-yard line where Michael Flynn screwed his shot horribly wide.
The Baggies then needed Kiely to produce a good save to his right to keep out McPhee's first-time shot from Burgess' knockdown.
Albion were seeing plenty of the ball but it was Pool who threatened again in the 61st minute when Evatt stole in at the back post to head Hoolahan's right-wing corner just over the bar.
In the 65th minute, Hoefkens bravely chased down Miller's flick-on from Clement's long diagonal ball and cut it back to the near-post where Evatt blocked Moore's goal attempt.
From the resulting Brunt flag-kick, Barnett headed wide of the near post.
Two minutes later, Mowbray made his final change as 22-goal top scorer Phillips replaced Brunt.
Albion were caught on the break in the 72nd-minute but got lucky when Taylor-Fletcher headed straight at Kiely from Burgess' left-wing centre.
Albion finally made Rachubka work for the first time in the 79th minute when Phillips swiveled on Greening's ball into the box and fired in a near-post strike, which the Pool keeper blocked.
Cue real drama, as Albion stunned Blackpool by scoring three times in six minutes.
In the 81st minute, Hoefkens charged into the box and referee Jonathan Moss pointed to the penalty spot after the Baggies right-back was brought down by Crainey.
Substitute Phillips stepped up to fire the spot-kick in off the left-hand post for his 23rd goal of the season.
Just three minutes later, Hoefkens fed Miller just inside the Albion half.
The powerhouse striker out-stripped Crainey before crossing to give Phillips a simple tap-in.
Incredibly, it was 3-1 in the 87th minute.
Robert Koren's gorgeous diagonal ball sent Miller away and he cut inside Crainey before cracking a left-footed shot into the far top corner.
Blackpool were shell-shocked and Robinson and Koren wasted further chances to extend Albion's lead.
BLACKPOOL (4-4-2): Rachubka; Barker, Gorkss, Evatt, Crainey; Hoolahan, Flynn (Southern 85), Jorgensen, Taylor-Fletcher; Burgess (Holt 85), McPhee (Dickov 77). Subs not used: Flinders (gk), Coid.
ALBION (4-3-3): Kiely; Hoefkens, Albrechtsen (Barnett 28), Clement, Robinson; Koren, Pele (Morrison HT), Greening; Brunt (Phillips 67), Miller, Moore. Subs not used: Bednar, Kim.
GOALS: BLACKPOOL - Burgess (35). ALBION - Phillips (81 pen, 84), Miller (87).
BOOKINGS: ALBION - Miller (over-celebrating 85), Moore (kicking ball away 85).
REFEREE: J Moss (W Yorkshire).
ATTENDANCE: 9,628.
ALBION STARMAN: Carl Hoefkens.
PIC: ALL SQUARE...Moore and Phillips celebrate the latter's equaliser from the spot
