They had only conceded 22 league goals this season and had kept 19 clean sheets, de Vries chasing Roger Freestone's club record of 22 shut-outs.
Blackstock had the ball in the back of the net after just three minutes, though, only to be denied by the linesman's flag.
Angel Rangel fired narrowly wide for the visitors with a half volley, before Forest saw Paul McKenna depart with injury after just seven minutes.
Mark Gower had a couple of chances for the Swans as they recovered from the early onslaught by the home side.
Dexter Blackstock was denied an early goal for offside
But the best chance of the half fell to Chris Cohen, who somehow volleyed over the bar from six yards after a good build-up from Swansea old-boy Paul Anderson.
Wales international Chris Gunter troubled the Swansea defence early in the second half, feeding Radoslaw Majewski who blazed over the bar from the edge of the area.
A number of referee Colin Webster's decisions had angered Swansea, but their fury spilled over when Cohen appeared to bring down Pratley in the box when the midfielder was through one-on-one with the keeper.
Shefki Kuqi created havoc for Gunter in the Forest box and fed Gower, who fired just wide.
At the other end, Alan Tate saved Ashley Williams' blushes after a defensive blunder from the Wales international.
But with Swansea eyeing their eighth goalless draw of the Championship campaign, Forest were awarded a corner when the visitors claimed they should have received a free-kick for offside.
Lewis McGugan took the kick, and as an advancing de Vries failed to gather at the near post defender Chambers found the ball placed on his head as he charged in at the back post to claim his first goal of the season.
Nottingham Forest manager Billy Davies: "I would not have been happy about [the penalty] but what goes around comes around and we have had decisions go against us in a lot of games.
Sousa rails at more 'bad decisions'
"On the balance of play I thought we just about deserved the win. We created the better chances.
"We should have gone ahead but Chris Cohen tried not to get his hair dirty when he had the chance to give us the lead.
"It's a big, big win for us and it's a tremendous achievement for this side to be where they are at this point of the season.
"This time last year 75% of them were fighting relegation and they deserve enormous credit for getting this club where it is now."
Swansea manager Paulo Sousa: "People who make mistakes are only human but what concerns me is that it is happening week by week with us.
Swansea's Tate furious at officials
"The stadium was in shock when we were not awarded the penalty. Everyone could see that it was but we didn't get what we deserved.
"If the decisions in our games had been the right decisions we would be close to the top of the division by now. It's happening too often and I hope someone can explain the situation to me.
"We are a team playing well, always looking to win games and gaining respect from the opposition but there is nothing we can do when we receive decisions like the ones we did.
"But we need to stand up our heads because we need to feel proud."
Live text and stats
Saturday, 6 March 2010
07 Anderson (McCleary 84)
18 McKenna (McGugan 7)
19 Moussi yellow card
28 Majewski (McGoldrick 76)
01 De Vries
12 Dyer (Van der Gun 46)
28 Butler (Beattie 85)
42 Kuqi yellow card
11 Van der Gun,
Ref: WebsterAtt: 25,012
Attempts on target
Attempts off target
90:00+4:06 The game is over, as the referee blows his whistle.
90:00+2:07 Outswinging corner taken right-footed by Mark Gower from the right by-line, save by Lee Camp.
90:00+1:56 Cedric Van der Gun has a drilled shot. Luke Chambers gets a block in.
90:00+0:33 Assist on the goal came from Lewis McGugan.
90:00+0:33 GOAL - Luke Chambers:Nottm Forest 1 - 0 Swansea Luke Chambers scores a headed goal from inside the six-yard box. Nottm Forest 1-0 Swansea.
90:00+0:07 Corner taken by Lewis McGugan,
87:23 Booking Booking for Shefki Kuqi.
86:51 Free kick awarded for a foul by Chris Gunter on Cedric Van der Gun. Dorus De Vries takes the free kick.
85:04 Foul by George Boyd on Mark Gower, free kick awarded. The free kick is swung in right-footed by Mark Gower, Wes Morgan manages
to make a clearance.
84:00 Free kick taken by Dorus De Vries.
84:00 Substitution (Swansea) makes a substitution, with Craig Beattie coming on for Thomas Butler.
84:00 David McGoldrick challenges Alan Tate unfairly and gives away a free kick.
83:07 Substitution Garath McCleary replaces Paul Anderson.
79:44 The ball is crossed by Lewis McGugan, save by Dorus De Vries.
75:41 Substitution David McGoldrick replaces Radoslaw Majewski.
73:41 Cedric Van der Gun produces a left-footed shot from the edge of the box and misses to the left of the target.
71:00 Corner taken by George Boyd, clearance made by Alan Tate.
69:37 Radoslaw Majewski takes a shot. Save by Dorus De Vries.
68:49 The referee penalises Darren Pratley for handball. Luke Chambers takes the free kick.
68:19 Foul by Mark Gower on George Boyd, free kick awarded. Lee Camp takes the direct free kick.
67:47 George Boyd takes a shot. Dorus De Vries makes a save.
66:23 The referee blows for offside. Free kick taken by Dorus De Vries.
65:52 Radoslaw Majewski delivers the ball, save by Dorus De Vries.
63:01 Cedric Van der Gun fouled by Paul Anderson, the ref awards a free kick. Free kick taken by Thomas Butler.
61:34 Paul Anderson produces a cross, clearance made by Alan Tate.
61:23 Lewis McGugan fouled by Darren Pratley, the ref awards a free kick. Lewis McGugan takes the free kick.
60:23 Chris Cohen sends in a cross.
58:49 Alan Tate concedes a free kick for a foul on Radoslaw Majewski. The free kick is swung in right-footed by Lewis McGugan, Angel
Rangel makes a clearance.
58:02 Unfair challenge on Leon Britton by George Boyd results in a free kick. Direct free kick taken by Alan Tate.
56:29 Chris Cohen sends in a cross, Leon Britton manages to make a clearance.
55:20 Unfair challenge on Guy Moussi by Leon Britton results in a free kick. Lewis McGugan takes the free kick.
54:17 Booking The referee shows Guy Moussi a yellow card for unsporting behaviour.
52:41 Shot from just outside the box by Radoslaw Majewski goes over the crossbar.
51:13 Handball by Leon Britton. Chris Cohen takes the direct free kick.
48:36 The assistant referee flags for offside against Shefki Kuqi. Lee Camp restarts play with the free kick.
48:04 Free kick awarded for a foul by Wes Morgan on Leon Britton. Alan Tate takes the free kick.
Correction - 47:00 Corner taken left-footed by George Boyd, save made by Dorus De Vries.
46:54 George Boyd takes the inswinging corner, save by Dorus De Vries.
46:19 Foul by Ashley Richards on Chris Gunter, free kick awarded. The free kick is delivered left-footed by George Boyd from right
wing, clearance made by Ashley Richards.
45:33 Shot from long distance by Shefki Kuqi goes wide of the left-hand post.
45:01 The game restarts for the second half.
45:01 Substitution Cedric Van der Gun replaces Nathan Dyer.
45:00+2:48 It is the end of the first-half.
40:00 Chris Cohen gives away a free kick for an unfair challenge on Darren Pratley. Thomas Butler crosses the ball in from the free
kick, Wes Morgan makes a clearance.
39:06 Guy Moussi concedes a free kick for a foul on Thomas Butler. Ashley Williams takes the direct free kick.
37:21 Chris Gunter concedes a free kick for a foul on Thomas Butler. Ashley Williams takes the direct free kick.
33:19 A cross is delivered by Paul Anderson, Close range shot by Chris Cohen clears the bar.
32:32 A cross is delivered by Radoslaw Majewski, Dorus De Vries makes a save.
28:26 Inswinging corner taken right-footed by Radoslaw Majewski.
26:59 George Boyd takes a shot. Save made by Dorus De Vries.
23:39 Radoslaw Majewski is penalised for handball and concedes a free kick. Free kick taken by Alan Tate.
23:11 Shefki Kuqi takes a shot from 30 yards. Lee Camp makes a save.
22:13 Shot from 18 yards by Shefki Kuqi. Save by Lee Camp.
21:00 Guy Moussi challenges Darren Pratley unfairly and gives away a free kick. Leon Britton takes the free kick.
19:43 Inswinging corner taken right-footed by Thomas Butler from the left by-line, Lee Camp makes a save.
19:09 Outswinging corner taken right-footed by Thomas Butler, clearance made by George Boyd.
18:34 Outswinging corner taken by Thomas Butler from the right by-line played to the near post, clearance by Dexter Blackstock.
18:25 A cross is delivered by Darren Pratley, blocked by Luke Chambers.
17:56 Unfair challenge on Alan Tate by Dexter Blackstock results in a free kick. Ashley Williams restarts play with the free kick.
17:15 Darren Pratley fouled by Luke Chambers, the ref awards a free kick. Direct free kick taken by Alan Tate.
11:37 Effort on goal by George Boyd from just inside the area clears the bar.
9:34 George Boyd fouled by Mark Gower, the ref awards a free kick. Free kick crossed by Radoslaw Majewski.
8:21 Paul Anderson crosses the ball, save by Dorus De Vries.
6:28 Substitution Lewis McGugan is brought on as a substitute for Paul McKenna.
5:27 A cross is delivered by Leon Britton, clearance by Luke Chambers.
4:04 Shot from outside the box by Angel Rangel misses to the left of the goal.
3:02 The offside flag is raised against Dexter Blackstock. Ashley Williams restarts play with the free kick.
2:02 Darren Pratley has an effort at goal from outside the area which goes wide left of the target.
0:47 The ball is crossed by George Boyd.
0:00 The game gets underway.
Live text and data provided by The Press Association.
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