Rickie Lambert scored in injury time but Championship leaders Southampton lost their 21-match winning home run.
Lambert, back in the team after injury, gave the home side the lead at St Mary's with a deflected shot before Chris Basham levelled with a header.
The visitors went ahead when Saints goalkeeper Bartosz Bialkowski somehow allowed Callum McManaman's scuffed shot to squirm through his hands and legs.
But Lambert headed the late equaliser with his 16th goal of the season.
Bialkowski, starting his first league match in two years after regular number one Kelvin Davis was ruled out with a groin problem, looked nervous from the outset.
The 24-year-old Polish under-21 international spilt a cross from Matt Phillips behind for a corner with his first touch and then made an unconventional save with his chest to keep out Ludovic Sylvestre's snapshot.
Southampton took the lead when Adam Lallana dispossessed Neal Eardley, passed to Jack Cork, who fed Lambert and the striker's shot took a big deflection off Craig Cathcart and flew past Matt Gilks.
The Seasiders levelled after Basham found space at the back post to head home McManaman's cross and almost took the lead when Phillips' 20-yard shot hit the foot of the post, with Bialkowski rooted to the spot.
And the inexperienced keeper's day took a turn for the worse just after half-time.
McManaman went on a mazy run into the area but his shot was tame, and the winger had already turned away to trot back up the pitch.
However, the ball went through Bialkowski's legs and rolled over the line, despite the keeper's desperate attemps to claw it back.
Shell-shocked Saints went in search of an equaliser but Gilks saved from Guly do Prado, Dean Hammond curled a shot just wide and substitute Steve de Ridder volleyed over.
But in the 93rd minute Frazer Richardson crossed into the area and Lambert powered his header past Gilks to snatch a crucial point.
Southampton manager Nigel Adkins: "Bart is always outstanding in training and he will be a stronger character for what happened to him.
"We will support him and help him get over this mistake and the good thing is we did not lose the game.
"As for the record, it had to go some time. If you had said at the start of the season we would win 10 and draw the other of our first 11 home games I would have taken it without a moment's hesitation.
"Teams are taking no chances when they come to our ground now, as you would expect, so it is often hard to break them down but at the end we might even have got a third goal."
Blackpool manager Ian Holloway: "I don't know where the officials got five minutes extra (from). How on earth they reached that number I just don't know.
"It is a bitter pill for us to swallow because I thought we were going to win and nobody has done that down here for a year.
"In the end I've got to be satisfied with a good draw but we could so easily have won it and that's why it feels a little bit like a defeat."
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Live Text Commentary
Full Time The referee blows his whistle to end the game.90:00 +4:41
Jos Hooiveld challenges Gary Taylor-Fletcher unfairly and gives away a free kick. Neal Eardley takes the direct free kick.90:00 +3:19
Adam Lallana gives away a free kick for an unfair challenge on Lomana Tresor LuaLua. Neal Eardley restarts play with the free kick.90:00 +2:40
The assist for the goal came from Frazer Richardson.90:00 +2:40 Goal scored
Goal! - Richard Lambert - Southamp'n 2 - 2 Blackpool Richard Lambert finds the back of the net with a headed goal from close range. Southampton 2-2 Blackpool.90:00 +2:37
A cross is delivered by Frazer Richardson,90:00 +1:53
Close range effort by Lomana Tresor LuaLua goes wide of the left-hand post.90:00 +0:47 Substitution
Substitution Thomas Ince on for Matt Phillips.90:00 +0:21
The ball is delivered by Richard Lambert. The ball is crossed by Dan Harding, Steve De Ridder has an effort from just inside the box that misses to the left of the goal.89:52
Guly Do Prado delivers the ball.88:25
Outswinging corner taken left-footed by Dan Harding from the left by-line, clearance by Gary Taylor-Fletcher.88:20
A cross is delivered by Dan Harding, Neal Eardley makes a clearance.86:56
Effort from inside the area by Steve De Ridder misses to the right of the goal.86:49
Frazer Richardson produces a cross, Craig Cathcart manages to make a clearance.86:23
Gary Taylor-Fletcher takes a shot. Blocked by Dan Harding.85:56
The ball is swung over by Stephen Crainey, Jos Hooiveld manages to make a clearance.85:23
Foul by Barry Ferguson on Morgan Schneiderlin, free kick awarded. Jose Fonte restarts play with the free kick.84:21
Steve De Ridder delivers the ball, clearance by Craig Cathcart.83:32
The referee blows for offside. Jose Fonte takes the indirect free kick.82:35
Guly Do Prado handles the ball and concedes a free kick. Barry Ferguson takes the free kick.
Substitution Chris Basham leaves the field to be replaced by Lomana Tresor LuaLua.81:03
Shot by Jos Hooiveld from deep inside the penalty area misses to the left of the goal.80:20
The free kick is swung in right-footed by Morgan Schneiderlin, clearance by Ian Evatt.80:20 Booking
Booking Chris Basham booked for unsporting behaviour.80:03
Dan Harding fouled by Chris Basham, the ref awards a free kick.78:56
Jack Cork gives away a free kick for an unfair challenge on Ludovic Sylvestre. Stephen Crainey takes the free kick.78:49
Frazer Richardson crosses the ball, Stephen Crainey gets a block in.77:56
Frazer Richardson sends in a cross, Adam Lallana takes a shot. Save made by Matthew Gilks.76:54
Jack Cork crosses the ball, Guly Do Prado has a header from close range and clears the crossbar.76:38
A cross is delivered by Frazer Richardson, Ian Evatt makes a clearance.76:12
Unfair challenge on Dan Harding by Kevin Phillips results in a free kick. Dan Harding takes the free kick.74:02 Substitution
Substitution Kevin Phillips joins the action as a substitute, replacing Callum McManaman.72:43
Foul by Chris Basham on Adam Lallana, free kick awarded. Morgan Schneiderlin crosses the ball from the free kick right-footed from left channel, Matthew Gilks makes a comfortable save.71:49
Dan Harding concedes a free kick for a foul on Matt Phillips. Free kick crossed left-footed by Stephen Crainey from right wing, clearance made by Jos Hooiveld.70:12
Ian Evatt restarts play with the free kick.70:12 Booking
Booking The referee cautions Morgan Schneiderlin for unsporting behaviour.70:07
Matt Phillips fouled by Morgan Schneiderlin, the ref awards a free kick.69:30
The ball is sent over by Steve De Ridder.69:13
The ball is crossed by Dan Harding, save by Matthew Gilks.68:30
Dan Harding takes a inswinging corner to the near post, Ludovic Sylvestre makes a clearance.68:22
The ball is sent over by Frazer Richardson, Stephen Crainey gets a block in.68:04
Morgan Schneiderlin sends in a cross, Craig Cathcart makes a clearance.67:46
Dan Harding sends in a cross, Matthew Gilks makes a save.66:38
Free kick awarded for a foul by Dan Harding on Gary Taylor-Fletcher. Barry Ferguson takes the free kick.66:12
Ian Evatt fouled by Steve De Ridder, the ref awards a free kick. Free kick taken by Matthew Gilks.65:10
Ian Evatt fouled by Steve De Ridder, the ref awards a free kick. Ian Evatt takes the direct free kick.61:49
Indirect free kick taken by Matthew Gilks.61:49 Substitution
Substitution Daniel Fox goes off and Dan Harding comes on.61:49 Substitution
Substitution Dean Hammond goes off and Steve De Ridder comes on.61:49 Booking
Booking Barry Ferguson goes into the referee's book.61:32 Booking
Booking Richard Lambert is booked.61:09
The referee blows for offside.60:29
The ball is sent over by Chris Basham, save by Bartosz Bialkowski.59:57
Jose Fonte challenges Gary Taylor-Fletcher unfairly and gives away a free kick. Stephen Crainey restarts play with the free kick.59:22
Dean Hammond produces a right-footed shot from the edge of the box and misses to the right of the target.58:34
Free kick awarded for a foul by Dean Hammond on Chris Basham. Direct free kick taken by Barry Ferguson.58:07
The ball is sent over by Adam Lallana. Close range header by Guly Do Prado goes wide of the left-hand upright.57:36
Daniel Fox takes a short corner.56:24
Gary Taylor-Fletcher fouled by Daniel Fox, the ref awards a free kick. Ludovic Sylvestre takes the direct free kick.55:50
Guly Do Prado takes a shot. Matthew Gilks makes a save.54:18
Jos Hooiveld concedes a free kick for a foul on Gary Taylor-Fletcher. Free kick crossed by Ludovic Sylvestre.53:57
Matt Phillips fouled by Morgan Schneiderlin, the ref awards a free kick. Barry Ferguson takes the direct free kick.53:30
The ball is crossed by Daniel Fox, clearance by Stephen Crainey.51:47
Neal Eardley crosses the ball.51:29
The ball is delivered by Neal Eardley, clearance by Jos Hooiveld.49:14
Foul by Richard Lambert on Ian Evatt, free kick awarded. Free kick taken by Matthew Gilks.48:13
Assist by Stephen Crainey.48:13 Goal scored
Goal! - Callum McManaman - Southamp'n 1 - 2 Blackpool Callum McManaman grabs a goal from just outside the area to the bottom left corner of the goal. Southampton 1-2 Blackpool.47:20
Daniel Fox produces a cross, blocked by Barry Ferguson.46:17
Inswinging corner taken by Daniel Fox, clearance made by Ian Evatt.46:04
Morgan Schneiderlin takes a shot. Ian Evatt gets a block in.45:47
Guly Do Prado takes a shot. Neal Eardley gets a block in.45:01
The second half begins.45:00 +2:08 Half time
Half Time The ref blows to signal half-time.45:00 +1:34
Morgan Schneiderlin produces a cross, Neal Eardley manages to make a clearance.43:32
Ludovic Sylvestre fouled by Jack Cork, the ref awards a free kick. The free kick is delivered left-footed by Stephen Crainey from left channel, Jos Hooiveld makes a clearance.42:56
Callum McManaman produces a left-footed shot from just outside the box that misses to the right of the target.41:01
Chris Basham fouled by Dean Hammond, the ref awards a free kick. Barry Ferguson takes the free kick.39:55
The free kick is swung in left-footed by Daniel Fox.39:55 Booking
Booking Ian Evatt booked for unsporting behaviour.39:50
Foul by Ian Evatt on Guly Do Prado, free kick awarded.39:25
The official flags Matt Phillips offside. Bartosz Bialkowski restarts play with the free kick.38:49
Matt Phillips takes a shot from outside the penalty box and strikes the post.38:25
Jack Cork takes a shot. Save by Matthew Gilks.35:28
Assist on the goal came from Callum McManaman.35:28 Goal scored
Goal! - Chris Basham - Southamp'n 1 - 1 Blackpool Chris Basham grabs a headed goal from close in. Southampton 1-1 Blackpool.35:25
A cross is delivered by Callum McManaman,33:18
Richard Lambert takes a shot. Save by Matthew Gilks. Adam Lallana decides to take the corner short. Adam Lallana takes a shot. Save made by Matthew Gilks.29:18
Assist by Jack Cork.29:18 Goal scored
Goal! - Richard Lambert - Southamp'n 1 - 0 Blackpool Richard Lambert grabs a goal from the edge of the penalty box high into the middle of the goal. Southampton 1-0 Blackpool.28:13
Neal Eardley produces a cross, Richard Lambert manages to make a clearance.28:02
Ludovic Sylvestre decides to take the corner short.27:50
A cross is delivered by Callum McManaman, clearance made by Daniel Fox.27:11
Free kick awarded for a foul by Richard Lambert on Craig Cathcart. Free kick taken by Craig Cathcart.26:37
The ball is delivered by Matt Phillips.25:47
Centre by Frazer Richardson, Shot by Dean Hammond from deep inside the six-yard box clear the bar.25:29
Barry Ferguson challenges Morgan Schneiderlin unfairly and gives away a free kick. Direct free kick taken by Jack Cork.25:13
Gary Taylor-Fletcher gives away a free kick for an unfair challenge on Jos Hooiveld. Direct free kick taken by Dean Hammond.24:23
A cross is delivered by Richard Lambert, Guly Do Prado produces a header from deep inside the six-yard box which goes wide of the right-hand upright.23:18
Jos Hooiveld fouled by Matt Phillips, the ref awards a free kick. Jos Hooiveld takes the direct free kick.21:12
Inswinging corner taken from the left by-line by Ludovic Sylvestre, Jos Hooiveld makes a clearance.18:27
A cross is delivered by Frazer Richardson.16:11
Adam Lallana delivers the ball. Shot on goal by Morgan Schneiderlin from inside the box goes harmlessly over the target.15:42
Shot from close in by Guly Do Prado misses to the left of the goal.15:16
Guly Do Prado crosses the ball, Matthew Gilks makes a comfortable save.14:45
The ball is crossed by Frazer Richardson, clearance by Ian Evatt.13:13
Ludovic Sylvestre takes a shot. Bartosz Bialkowski makes a save.12:38
Centre by Morgan Schneiderlin.10:59
Unfair challenge on Barry Ferguson by Jack Cork results in a free kick. Barry Ferguson takes the direct free kick.6:01
Foul by Callum McManaman on Morgan Schneiderlin, free kick awarded. The ball is sent over by Daniel Fox, Header from close range by Jos Hooiveld misses to the right of the goal.5:52
Morgan Schneiderlin crosses the ball, Ian Evatt makes a clearance.4:08
Close range effort by Gary Taylor-Fletcher goes wide of the right-hand upright.3:51
Ludovic Sylvestre decides to take a short corner.3:34
The ball is delivered by Neal Eardley, clearance made by Adam Lallana. The ball is crossed by Matt Phillips, save by Bartosz Bialkowski.2:36
The ball is delivered by Jack Cork.2:13
The ball is crossed by Frazer Richardson, blocked by Stephen Crainey.0:00
The match begins.
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