Match ends, Nottingham Forest 2, Newcastle United 1.
Championship leaders Newcastle had two men sent off and keeper Karl Darlow saved two penalties before falling to a late defeat at Nottingham Forest.
Matt Ritchie gave the Magpies a 1-0 lead at half-time, despite red cards for Jonjo Shelvey and Paul Dummett.
Both dismissals resulted in penalties, with Darlow saving from Nicklas Bendtner and Henri Lansbury.
Bendtner equalised from close range and Forest won it when former player Jamaal Lascelles bundled into his own net.
Newcastle were left incensed by referee Steve Martin's decision to dismiss Dummett, and then not allow a Ciaran Clark header which looked legitimate.
Though still top by two points, Newcastle have lost back-to-back league games for the first time since the opening two matches, while Forest, with three wins on the trot, are up to 13th.
There was little warning of the excitement to follow after a fairly nondescript first 30 minutes in soggy conditions, but the game roared into life with a following hour that had everything - controversy, drama and goals.
Shelvey was dismissed for kicking out at Lansbury, but Forest failed to capitalise as Bendtner's penalty was saved by another former Forest player Darlow.
Ritchie's well-taken shot was Newcastle's just reward for their dominance in possession, and Darlow protected that lead from Lansbury's penalty, although the decision to send off Dummett for pushing over Lansbury when last man was far less clear cut.
Bendtner's effort, scrambled home from close in, suggested Forest would pour forward with their two extra men, but there was no anticipated onslaught.
The late winner, cruel as it was on Lascelles, was as much about Newcastle's fatigue as it was the home side's incision.
Nottingham Forest head coach Philippe Montanier told BBC Radio Nottingham:
"It was a crazy game, when you see a goalkeeper save two penalties in a game where 11 are against nine and you score at the end - there is a lot of emotion.
"Three points are very important for us, it was tough and I knew before it would be, but not like this.
"We had to be patient, to play wide and to deliver a lot of crosses, we respected the plan and we had a patience until the end.
"[Regards the incidents] I would like to see the video even though we can't change the referee's decision."
Newcastle United manager Rafael Benitez told BBC Newcastle:
"It's very difficult to understand what happened, we can complain about the penalty not given, the goal offside, the [Forest] penalty given and the two red cards.
"I haven't spoken to the referee, I don't need to do it, I've seen the images and it's obvious and clear to me.
"We did really well, we were doing what we had to do but it's a big difference when you have 45 minutes numerical inferiority it's not easy."
- 4MancienneBooked at 44minsSubstituted forAssombalongaat 45'minutes
- 10LansburyBooked at 72mins
- 28LamSubstituted forCarayolat 65'minutes
- 14BendtnerSubstituted forVelliosat 79'minutes
- 26DarlowBooked at 45mins
- 22YedlinBooked at 90mins
- 3DummettBooked at 45mins
- 12ShelveyBooked at 33mins
- 17PérezSubstituted forAnitaat 45'minutes
- 20GouffranBooked at 53minsSubstituted forDiaméat 77'minutes
- 9GayleSubstituted forMitrovicat 87'minutes
- Steve Martin
- Shots on Target
Second Half ends, Nottingham Forest 2, Newcastle United 1.
Attempt missed. Henri Lansbury (Nottingham Forest) right footed shot from outside the box misses to the left. Assisted by Ben Osborn from a direct free kick.
DeAndre Yedlin (Newcastle United) is shown the yellow card for a bad foul.
Eric Lichaj (Nottingham Forest) wins a free kick in the attacking half.
Foul by DeAndre Yedlin (Newcastle United).
Foul by Matt Mills (Nottingham Forest).
Aleksandar Mitrovic (Newcastle United) wins a free kick in the attacking half.
Foul by Pajtim Kasami (Nottingham Forest).
DeAndre Yedlin (Newcastle United) wins a free kick on the right wing.
Offside, Nottingham Forest. Matt Mills tries a through ball, but Apostolos Vellios is caught offside.
Eric Lichaj (Nottingham Forest) wins a free kick in the defensive half.
Foul by Isaac Hayden (Newcastle United).
Attempt saved. Pajtim Kasami (Nottingham Forest) left footed shot from outside the box is saved in the centre of the goal. Assisted by Ben Osborn.
Substitution, Newcastle United. Aleksandar Mitrovic replaces Dwight Gayle.
Own Goal by Jamaal Lascelles, Newcastle United. Nottingham Forest 2, Newcastle United 1.
Corner, Nottingham Forest. Conceded by Mohamed Diamé.
Attempt blocked. Eric Lichaj (Nottingham Forest) right footed shot from the left side of the box is blocked.
Attempt missed. Ben Osborn (Nottingham Forest) left footed shot from outside the box misses to the left.
Dwight Gayle (Newcastle United) wins a free kick in the defensive half.