Reading let slip of a two-goal lead as Blackpool made a remarkable recovery with three second-half goals to take the points.
Goals from Scott Dann and Tom Dele-Bashiru put the Royals in front in the first-half, but Blackpool hit back with two quickfire goals in the second-half.
The away side then completed their impressive turnaround as Jerry Yates netted his second from the penalty spot to give them an 85th minute winner.
Reading are in eighth in the Championship table as they missed out on the chance to move into the play-off places with a win.
Veljko Paunovic named an unchanged side from Reading’s 1-0 win over Barnsley as the Royals made it five wins from the last six league matches.
The Royals made a slow start and were on the back foot early as the visitors enjoyed a spell of possession and won a corner after Andy Yiadom blocked James Husband’s cross from the left.
Reading managed to regroup after they cleared the set-piece with ease and begun to find their feet in the match.
Ovie Ejaria was his usual creative self down the left and his quick feet won Reading a free-kick wide on the left.
Just as the rain started to pour from the Berkshire sky, Reading lightened the mood as they went in front with their first chance of the game.
Having linked up for Saturday’s winner against Barnsley, the roles were reversed this time around as Swift turned provider for Dann who got on the end of the inswinging free-kick and glanced a header into the far corner.
Swift now has 14 goal contributions in the league this season (eight goals, six assists).
The visitors responded by winning a couple of corners as Husband got forward from full-back brightly and provided a threat on the left-wing. But they didn’t take advantage as Luke Southwood came off his line with a well taken catch.
The Tangerines should have found themselves level but were thwarted by two excellent pieces of goalkeeping from Southwood who produced a magnificent double stop.
He first got down low to his right to parry away a low drive from Jordan Gabriel, but the ball fell into the path of Shayne Lavery who looked certain to equalise but the Royals keeper reacted quickly to block his effort from point blank range.
Just two minutes after surviving that scare from the visitors, Reading extended their advantage as Dele-Bashiru netted his third Championship goal of the season.
George Puscas rolled the ball into the path of Josh Laurent who looked poised to shoot in front of goal, but he unselfishly squared the ball to Dele-Bashiru who had a routine finish to tuck the ball past the stranded goalkeeper.
Neil Critchley’s side were down but not out as they found their fair share of chances, with the next one coming from a central free-kick from shooting range but Keshi Anderson smashed the ball high into the stands.
Blackpool then stole the ball and hit Reading on the counter attack, but again missed a golden chance to score as Royals skipper Liam Moore got across to make a heroic last ditch block on Anderson.
The final chance of the half fell for the visitors with a free-kick just outside the box. This time Demetri Mitchell tried his luck as he looked to beat Southwood on his side but hit his effort wide of the target.
The half started with a big chance for the hosts to add a third goal as Puscas raced away from the Blackpool defence, but Daniel Grimshaw got the better of him in the one-on-one battle as the striker still searches for his first goal of the season.
Blackpool wanted a penalty in the 52nd minute when Jerry Yates went down in the box under the challenge of Southwood, but the referee judged that the striker had simulated contact and he was shown a yellow card.
The away side received another yellow card for simulation when Mitchell threw himself to the floor in the box.
Yates had a chance in front of goal for Blackpool as he stretched to try and meet the loose ball but he lost his footing at the vital moment and couldn’t hook the ball goalwards.
Reading’s first change of the night came in the 67th minute when Puscas was replaced by Femi Azeez.
Blackpool were rewarded for their positive play in the second-half and pulled a goal as Owen Dale’s bouncing shot took a slight deflection off Dann and found its way past Southwood in the 69th minute.
And just four minutes later the Tangerines were level as Yates escaped his marker at the far post and headed in from Dale’s cross.
With momentum firmly on their side, Blackpool went in search of a winner as Southwood made a smart stop from a free-kick.
Blackpool were then given the chance to complete their unlikely turnaround as Yiadom fouled Sonny Carey in the box.
Yates stepped up to the spot and beat Southwood with a powerful strike despite the Reading keeper getting fingertips to the ball to win the points for Blackpool.
Reading are away at Blackburn Rovers on Saturday (3pm).
Reading: Southwood, Yiadom, Moore (c), Dann, Rahman, Laurent, Drinkwater, Dele-Bashiru, Ejaria, Swift, Puscas
Rafael, Holmes, Azeez, Camara, Ehibhatiomhan, Clarke, Ashcroft
Blackpool: Grimshaw, Husband, Gabriel, Wintle, Yates, Anderson, Dougall, Mitchell, Carey, Ekpiteta (c), Keogh
Subs: Moore, Connolly, Dale, Bowler, Madine, John-Jules, Garbutt
Goals: Dann 11′, Dele-Bashiru 21′, Dale 69, Yates 73′, 85′ (pen)
