Nottingham Forest v Arsenal RESULT: Arsene Wenger's FA Cup holders eliminated following six-goal thriller

Read Sportsmail's Matt Barlow's account of an extraordinary afternoon of FA Cup football at the City Ground.

NOTTINGHAM FOREST 4-2 ARSENAL

The referee blows on the dot and that's it, the FA Cup holders Arsenal are eliminated in the third round.

This will go down as a classic and be recounted for many years.

Two penalties, one red card, countless twists and turns. FA Cup football at its finest.

92mins: meanwhile Arsenal bomb up the other end and Smith makes amends for his earlier error by pulling off an incredible save, nipping the ball mid-flight to send it safely around his post.

Walcott cannot get onto it before it drifts out of play.

Take a look at Dowell's standing leg. 

The Forest man slipped just before contact, which appeared to make him hit the shot off his planted leg.

The ref discussed with his assistant, and deemed all was fine.

This is madness, it really is.

We now have a red card. A second yellow for Joe Worrall sees him walk.

Arsenal need two goals, Forest are down to 10-men.

In the melee of all that David Ospina and Per Mertesacker have both been booked.

86mins: Cash off for McKay (Forest)

Debuchy off for Akpom (Arsenal)

He scored, but slipped in the process. Ref decides whether it's a double touch but.... THE GOAL IS GIVEN.

NOTTINGHAM FOREST 4-2 ARSENAL

This is getting ridiculous. What a cup tie.

Forest hammer up field on the the counter and Debuchy brings down his man. It's debatable, but it's given.

82mins: Arsenal press forward, and a ball into the box from Maitland-Niles sees Welbeck go down under the pressure of Mancienne.

The Gunners scream for a pen, but the ref looks the other way.

Forest are still digging in, refusing to let go of what would be an incredible result.

Meanwhile Forest dart up the other end and.......

It's a horror moment for goalkeeper Jordan Smith. 

He comes out to dive at the feet of Welbeck after a ball is played through... but lets it squeeze through his body.

Welbeck can't believe his luck, and flicks the ball over the line.

Perhaps undeserved, but it's game on.

NOTTINGHAM FOREST 3-2 ARSENAL

77mins: Walcott gets in behind and hits a first time cross, but the lunging Michael Mancienne is there to hack it away. 

It's the difference between the two sides here. One team wants it, the other doesn't.

74mins: Dowell whips the ball away from Holding and leaves him for dead. 

He drives to the byline and pulls the ball back to the edge of the six-yard box, but can't find a red shirt.

Arsenal's back line have been so, so poor.

70mins: Goalkeeper Smith somes to the rescue for Forest, after Nketiah gets played through and aims a low shot on goal.

It's mopped up by the defence, who are doing everything to get the ball away. Huge resilient being shown by the home side.

Arsene Wenger is in the stands surrounded by Nottingham Forest fans and is being asked whether he saw that penalty incident or not. This is a very bad afternoon for the Arsenal manager, who is paying the price for fielding a far weaker team than he usually does at this stage.

Forest caretaker manager Gary Brazil is showing his quality again. He makes a habit of stepping in to steady the ship and is a picture of animation on the touchline, cajoling his players on. 

67mins: Arsenal know they have to make amends. 

They press forward and win a corner, Walcott takes but it's hoofed away by Matty Cash.

Meanwhile, Arsenal bring on Eddie Nketiah for Joe Willock.

The 18-year-old steps up, places the ball, and smashes it home.

It's what he deserves, after being so influential in the final third. 

A huge uphill task for Arsenal now...

It's clumsy from Arsenal, and Rob Holding.

Forest were pressing into the box and Holding fells Cash as he comes bounding in. Clear pen.

60mins: Walcott pings it in and Welbeck is close to getting a touch, but goalkeeper Smith claims it with authority. 

Forest go straight up to the other end and almost score!

Sub Walker arrows in a cross and Brereton makes contact, but it's flicked behind for a corner.

59mins: Forest clear and now, interestingly, Arsenal look to be mirroring the approach of their opponents.

The last couple of minutes have seen a series of long balls sent over the top for Walcott to run on to.

Very un-Arsenal like, but it's won them a freekick here.

57mins: Nelson takes three players on out wide and bamboozles his way towards the edge of the box.

Forest manage to clatter the ball away, but it's soon back at them.

Walker comes on to replace Zach Clough.

54mins: Tyler Walker is being prepared by Forest, looks set to be the first change in this game.

Meanwhile Maitland-Niles dinks a testing cross into the area, but can't find a fellow Arsenal head.

52mins: Willock drives through the middle to find Nelson out wide. 

Arsenal make too much out of it, tapping the ball around hesitantly.

It's cleared and Forest sit in two solid banks once more, leaving Wenger's side to play short passes on the half-way line. This could be a long second half.

48mins: It's that ball over the top to Brereton again.

He races ahead and leaves Mertesacker eating dust. Arsenal manage to scramble bodies back to deal with it, but the hosts are sticking to their game plan.

We're back under way for the second 45.

No changes made by either side.

An omen - each time Forest have gone ahead this season, they haven't been beaten...

It’s been a vibrant atmosphere at the City Ground to mirror Gary Brazil’s young team.

The hosts have been worth this half-time lead, constantly looking to hurt Arsenal rather than use possession without effect.

Arsenal have got into good positions but rarely prised open the Forest defence. And there is not much to alter matters on the bench.

The City Ground exploded when Eric Lichaj's second goal hit the back of the net.

Rightly so... what, an, effort.

Wenger is heading down to the tunnel.

His ban means he's got to stay in the stands, but he can address the players at half-time.

Can't imagine he's going to have nice things to say...

It's that man again, and this one is a beauty. 

Cash crossed the ball, looking for Brereton. It was headed out by Mertesacker, but only as fas as Lichaj on the edge.

He takes it on the chest, cool, calm, and composed.

As it drops he unleashes a sublime, looping volley. Straight over Ospina and into the back of the next. 

Take a bow son.

Stoppage - Ospina is down and he's clutching his finger. Looks to be in pain, but seems he will play on.

41mins: It's happened again, Brereton in behind with a ball over the top.

He burns down the left and rockets a shot, but again it is saved by Ospina. 

Forest are knocking on the door, but Arsenal quickly head onto the counter once more.

38mins: Walcott works his way into the box with a jinking run and pulls the ball back, only for Lichaj to clear. 

Arsenal the more creative in attack, but Forest remain solid at the back.

35mins: Forest cleared their lines, but the ball is going back and forth at pace now.

Cash and Brereton are linking up well, the former finding the latter's driving runs with pinpoint passes.

So far, that duo look to be key if Forest are to retake the lead here.

32mins: And it's that man Brereton again. Forest are looking to find him at every opportunity. 

He cuts inside and goes around Mertesacker before hitting a low effort, the angle against him.

It would probably have found the bottom corner, if not for Ospina. Another top save.

At the other end Arsenal have a corner...

31min: Willock sends a searching cross over to find Iwobi. Arsenal manage to flick it around the opposition box, spreading panic.

They lose patience though, and Iwobi curls it into row Z.

27mins: This game has become far more open.

Forest have been rocked by Arsenal's quick reply, and find themselves with work to do.

As a result the Gunners' line is now much higher. Chances of the counter attack increased, you'd think.

Walcott whips it in and the ball is deflected onto the post.

It causes confusion and the big German is there to tuck the ball home.

Forest's lead didn't last long, we're all square.

22mins: Arsenal win a free-kick on the edge, chance to make instant amends.

The hosts take the lead! Dowell smashes a freekick into the box and Lichaj gets ahead of Ospina at the near post, burying a header in the top of the net.

The defending champions go behind.

17mins: A top save from Ospina, but a huge chance for Forest!

Clough splits Arsenal apart and finds Cash, whose shot was destined for the bottom corner.

Great fingertips from the Arsenal 'keeper, who was at full stretch to keep his team level.

16mins: Former Gunner Armand Traore uses his strength to battle with Walcott and win his side a goalkick. 

Forest looking to get the ball straight up to Brereton at all opportunities.

13mins: Walcott's looping cross finds Welbeck, but he can't get his header on target.

Despite fielding a weakened side, this Arsenal front line are strong.

10mins: Sustained pressure from the hosts wins a corner. 

Forest showing willing here, with Arsenal standing firm.

Maitland-Niles sees away the danger and makes off up field with the ball.

6mins: Brereton through again, off the shoulder of Mertesacker. 

He shoots from wide, though Ospina is down low to deal with it.

The ball clears and Arsenal get straight on the attack, Theo Walcott looks to square the ball across the box but scuffs it. End to end.

5mins: Brereton goes through at the other end after the corner is cleared, but official Sian Massey-Ellis flags for offside. It was a narrow call, but perhaps the right one.

The Forest man was through on goal otherwise.

3mins: Early signs showing Forest want to press high.

It's always a tricky approach with Arsenal, as they can catch you fast.

The Gunners are playing out of danger with ease so far, and have won an early corner.

NOTTINGHAM FOREST: Smith, Lichaj, Worrall, Mancienne, Traore, Osborn, Vaughan, Brereton, Dowell, Cash, Clough

ARSENAL: Ospina, Debuchy, Mertesacker, Holding, Nelson, Willock, Elneny, Maitland-Niles, Walcott, Iwobi, Welbeck

And we're under way at the City Ground!

The players are moments away from emerging, Arsene Wenger has taken his unfamiliar place in the stands, and we're almost ready.

Kick-off now minutes away.

Supporters now descending en masse to the City Ground. Perfect conditions today, if a little chilly.

Kick-off in just under 20 minutes.

Arsene Wenger has arrived at the City Ground looking cheerful.

He won't be involved much though, as his touchline ban takes hold.

How much will this affect things, we wonder?

You have to go back a couple of years to find the last time these two sides met.

Late September, 2016, the League Cup.

Forest hosted the Gunners, with disastrous consequences.

Goals from Granit Xhaka, Alex Oxlade-Chamberlain and a Lucas Perez doubled saw Arsenal romp to a 4-0 victory.

Today we ready ourselves for Arsenal returning to action, making their FA Cup third round bow against Nottingham Forest.

The City Ground will play host to the occasion, while Arsenal will be playing today's match without manager Arsene Wenger, who is suspended.

Stay tuned for full team news, coming up shortly.