Substitute Adam Le Fondre scored a late double as Reading fought back from two behind against Chelsea to climb out of the Premier League relegation zone.
Blues midfielder Juan Mata opened the scoring in first-half injury-time with a fierce strike across Adam Federici.
Frank Lampard's thumping header from Mata's corner put third-placed Chelsea firmly in command at the Madejski.
"Chelsea were two goals up with two minutes of normal time to play and Brian McDermott's team got a precious point from a terrific comeback. Again a battling, brave night for the Royals - but Chelsea know they have thrown it away."
But Le Fondre fired in Hope Akpan's pass before guiding in a stoppage-time leveller in a dramatic finale.
Reading knew they only needed a point to move above relegation rivals Wigan and Aston Villa out of the bottom three, but seemed set to remain in danger as Chelsea took command.
However, the Royals were rescued once again by Le Fondre, who also came off the bench to score twice in six minutes in their 2-1 win at Newcastle.
The introduction of fellow substitute Akpan, a recent signing from League One side Crawley Town, also proved instrumental as he provided both goals for Le Fondre.
His clever throughball enabled Le Fondre to fire past stand-in Chelsea goalkeeper Ross Turnbull, again replacing the injured Petr Cech, at his near post.
Turnbull had not even been forced into a save before Le Fondre's first and was left stunned as the ex-Rotherham striker earned Reading an unlikely point in the fifth minute of stoppage time.
Home goalkeeper Federici launched a long free-kick into the Chelsea box and the visiting defence, minus John Terry who was on the bench, failed to cope with the high ball.
It allowed Jimmy Kebe, and then Akpan, to head into the path of Le Fondre, who managed to keep his composure and score his seventh goal in five matches.
Chelsea were left stunned by the double salvo, which will crank up the pressure on Blues boss Rafael Benitez - again the target of jeers from the away supporters.
The visitors were firmly on course to secure their fifth successive top-flight victory on the road and reduce the deficit on second-placed Manchester City to four points.
A dull first-half sparked into life 50 seconds into stoppage-time as Reading were carved open by a slick one-touch move from the visitors.
Ramires, Oscar and Mata combined for Fernando Torres to scoop the ball into the path of fellow Spaniard Mata who swept a low half-volley across Federici into his bottom left-hand corner.
Reading have the Blues
Despite their remarkable comeback, the 2-2 draw means Reading have failed to beat Chelsea in Berkshire since a 3-1 win in March 1930.
Before Mata's goal, Chelsea's only periods of sustained pressure came after mistakes from Reading carelessly handed possession back to Blues.
And another error allowed Lampard to burst forward as Chelsea forced the corner which led to his goal.
It was the England midfielder's 10th goal of the season and puts him just six goals adrift of Bobby Tambling's all-time record of 202 goals for the west London club.
Brazilian midfielder Oscar could have added a third when he was released by substitute Yossi Benayoun's pass, only to be denied by the on-rushing Federici.
And it proved costly as Le Fondre intervened to earn Reading's seventh point from their last three Premier League games.
Reading boss Brian McDermott:
"You definitely didn't see that coming. But we've had it here at the Madejski before with 10 minutes to go. We've done it so many times.
"We weren't really in the game, just trying to get a foothold and trying to change things to get something.
"Hope Akpan came on the pitch and made a couple of goals too. He was terrific.
"That's why we talk about the group and what they all mean to us. They all made a difference for us today."
- 01 Federici
- 05 Pearce
- 06 Mariappa
- 23 Harte
- 27 Kelly
- 04 Karacan (Akpan - 77' )
- 08 Leigertwood
- 11 McAnuff Booked (Le Fondre - 66' )
- 14 Kebe
- 20 Guthrie (McCleary - 58' )
- 07 Pogrebnyak
- 41 Taylor
- 03 Shorey
- 15 Morrison
- 19 Robson-Kanu
- 28 Akpan
- 09 Le Fondre
- 12 McCleary
- 22 Turnbull
- 02 Ivanovic
- 03 Cole
- 24 Cahill
- 28 Azpilicueta Booked
- 34 Bertrand
- 07 Ramires Booked
- 08 Lampard
- 10 Mata (Benayoun - 77' )
- 11 Oscar
- 09 Torres (Ba - 90' )
- 40 Hilario
- 19 Ferreira
- 26 Terry
- 21 Marin
- 30 Benayoun
- 57 Ake
- 29 Ba
Live Text Commentary
Full Time The match has reached full-time.90:00 +5:27
Direct free kick taken by Adam Federici.90:00 +5:27 Booking
Booking Cesar Azpilicueta is shown a yellow card for unsporting behaviour.90:00 +5:22
Cesar Azpilicueta gives away a free kick for an unfair challenge on Adam Le Fondre.90:00 +4:07
Assist by Hope Akpan.90:00 +4:07 Goal scored
Goal! - Adam Le Fondre - Reading 2 - 2 Chelsea Goal scored by Adam Le Fondre from deep inside the penalty box to the top right corner of the goal. Reading 2-2 Chelsea.90:00 +3:41
Yossi Benayoun challenges Garath McCleary unfairly and gives away a free kick. Adam Federici takes the free kick.90:00 +1:15 Substitution
Substitution Demba Ba replaces Fernando Torres.90:00 +0:23
Nascimento Ramires takes a shot. Adam Federici makes a brilliant save.89:34
Fernando Torres is flagged offside by the assistant referee. Indirect free kick taken by Adam Federici.86:48
Assist by Hope Akpan.86:48 Goal scored
Goal! - Adam Le Fondre - Reading 1 - 2 Chelsea A goal is scored by Adam Le Fondre from inside the six-yard box to the bottom left corner of the goal. Reading 1-2 Chelsea.86:14
Cesar Azpilicueta gives away a free kick for an unfair challenge on Garath McCleary. Direct free kick taken by Adam Federici.85:00
Emboaba Oscar takes a shot. Save by Adam Federici.83:39
Shot from just outside the box by Adam Le Fondre misses to the right of the goal.80:45
Hope Akpan takes a shot from long distance which goes wide of the right-hand post.80:17
Nascimento Ramires gives away a free kick for an unfair challenge on Hope Akpan. Free kick taken by Adam Federici.79:13
Unfair challenge on Emboaba Oscar by Stephen Kelly results in a free kick. Branislav Ivanovic takes the free kick.78:46
Fernando Torres gives away a free kick for an unfair challenge on Adrian Mariappa. Ian Harte takes the direct free kick.77:34
Free kick awarded for an unfair challenge on Pavel Pogrebnyak by Gary Cahill. Ian Harte delivers the ball, Headed effort from inside the area by Adam Le Fondre misses to the right of the goal.
Free kick taken by Adam Federici.75:58 Substitution
Substitution Yossi Benayoun replaces Juan Mata.75:58 Substitution
Substitution (Reading) makes a substitution, with Hope Akpan coming on for Jem Karacan.75:58
The assistant referee flags for offside against Ryan Bertrand.74:41
Fernando Torres has an effort at goal from deep inside the area missing to the left of the goal.74:06
Juan Mata takes a outswinging corner from the left by-line played to the near post, clearance by Mikele Leigertwood.71:21
The referee blows for offside against Fernando Torres. Free kick taken by Adam Federici.66:37
Frank Lampard produces a right-footed shot from just outside the box that goes wide left of the goal.65:53 Substitution
Substitution Adam Le Fondre joins the action as a substitute, replacing Jobi McAnuff.65:02
Juan Mata provided the assist for the goal.65:02 Goal scored
Goal! - Frank Lampard - Reading 0 - 2 Chelsea Frank Lampard scores a headed goal from deep inside the penalty area. Reading 0-2 Chelsea.64:35
Juan Mata takes a outswinging corner from the left by-line to the near post,61:40
Unfair challenge on Jimmy Kebe by Ashley Cole results in a free kick. The free kick is swung in left-footed by Ian Harte, Nascimento Ramires manages to make a clearance.58:50
Nascimento Ramires gives away a free kick for an unfair challenge on Pavel Pogrebnyak. Ian Harte takes the direct free kick.57:10
Ross Turnbull takes the free kick.57:10 Substitution
Substitution Garath McCleary replaces Danny Guthrie.57:10
The assistant referee flags for offside against Pavel Pogrebnyak.56:24
Free kick awarded for an unfair challenge on Danny Guthrie by Nascimento Ramires. Ian Harte restarts play with the free kick.54:49
Emboaba Oscar has an effort at goal from deep inside the area missing to the left of the target.53:09
Handball decision goes against Emboaba Oscar. Adam Federici takes the free kick.51:57
Pavel Pogrebnyak fouled by Branislav Ivanovic, the ref awards a free kick. Ian Harte restarts play with the free kick.51:06
Unfair challenge on Adrian Mariappa by Ryan Bertrand results in a free kick. Free kick taken by Adam Federici.48:28
Alex Pearce challenges Fernando Torres unfairly and gives away a free kick. Frank Lampard has a direct shot on goal from the free kick.45:51
Unfair challenge on Stephen Kelly by Ryan Bertrand results in a free kick. Direct free kick taken by Adam Federici.45:01
The referee gets the second half started.45:00 +1:41 Half time
Half Time The players leave the pitch at half time.45:00 +0:42
The assist for the goal came from Fernando Torres.45:00 +0:42 Goal scored
Goal! - Juan Mata - Reading 0 - 1 Chelsea Juan Mata fires in a goal from close range to the bottom right corner of the goal. Reading 0-1 Chelsea.44:07
The assistant referee flags for offside against Juan Mata. Free kick taken by Adam Federici.42:36
Free kick awarded for an unfair challenge on Danny Guthrie by Ryan Bertrand. Free kick taken by Danny Guthrie.42:01
Ashley Cole produces a left-footed shot from the edge of the box and misses to the left of the target.40:36
Fernando Torres produces a right-footed shot from the edge of the area and misses to the left of the target.39:27
Ian Harte takes the free kick.39:27 Booking
Booking Nascimento Ramires receives a yellow card.39:17
Pavel Pogrebnyak fouled by Nascimento Ramires, the ref awards a free kick.37:03
Ryan Bertrand produces a left-footed shot from just outside the box that goes wide right of the goal.36:12
The official flags Pavel Pogrebnyak offside. Free kick taken by Gary Cahill.35:25
Free kick awarded for a foul by Jimmy Kebe on Ryan Bertrand. Ashley Cole restarts play with the free kick.34:08
Adrian Mariappa challenges Juan Mata unfairly and gives away a free kick. Free kick crossed left-footed by Juan Mata from right channel, clearance made by Alex Pearce.32:10
Danny Guthrie challenges Juan Mata unfairly and gives away a free kick. Direct free kick taken by Juan Mata.31:03
Jem Karacan is flagged offside by the assistant referee. Ross Turnbull takes the indirect free kick.30:25
Cesar Azpilicueta challenges Jobi McAnuff unfairly and gives away a free kick. Ian Harte restarts play with the free kick.28:13
Frank Lampard crosses the ball, Gary Cahill has a headed effort at goal from just inside the box that misses to the left of the goal.28:13 Booking
Booking Jobi McAnuff shown a yellow card.27:47
Foul by Jobi McAnuff on Emboaba Oscar, free kick awarded.24:28
Foul by Fernando Torres on Alex Pearce, free kick awarded. Adam Federici restarts play with the free kick.23:43
Pavel Pogrebnyak concedes a free kick for a foul on Gary Cahill. Free kick taken by Branislav Ivanovic.21:01
Corner taken left-footed by Juan Mata from the left by-line, clearance made by Alex Pearce.20:06
Fernando Torres is caught offside. Alex Pearce restarts play with the free kick.16:03
Foul by Pavel Pogrebnyak on Frank Lampard, free kick awarded. Branislav Ivanovic takes the direct free kick.14:52
Frank Lampard challenges Danny Guthrie unfairly and gives away a free kick. Adam Federici takes the direct free kick.13:32
Ashley Cole produces a left-footed shot from just outside the penalty area that goes harmlessly over the target.11:12
Free kick awarded for a foul by Branislav Ivanovic on Pavel Pogrebnyak. Free kick crossed right-footed by Danny Guthrie.10:41
Jimmy Kebe sends in a cross.6:24
Stephen Kelly fouled by Fernando Torres, the ref awards a free kick. Alex Pearce restarts play with the free kick.5:36
Inswinging corner taken left-footed by Juan Mata from the right by-line, Header on goal by Branislav Ivanovic from just inside the area goes over the target.4:18
Frank Lampard takes the inswinging corner, clearance made by Mikele Leigertwood.3:38
Juan Mata takes the inswinging corner, clearance made by Mikele Leigertwood.1:31
The official flags Pavel Pogrebnyak offside. Branislav Ivanovic restarts play with the free kick.0:16
Free kick awarded for an unfair challenge on Pavel Pogrebnyak by Branislav Ivanovic. Ian Harte crosses the ball in from the free kick.0:00
The ref blows the whistle to start the match.
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