For the first time in 21 years Arsenal have been knocked out of the FA Cup in the third round. An embarrassing 4-2 defeat against Nottingham Forest was the Gunners' downfall as Arsene Wenger witnessed his side crash out from the stands.
Eric Lichaj's double and penalties from Ben Brereton and Kieran Dowell saw off the Gunners who struggled to muster much in the sense of attacking play as Per Mertesacker and Danny Welbeck netted for Arsenal.
It was a humiliating result for the holders, who despite their record 13 triumphs, for once had to make do with misfortune in a competition which has previously brought them great luck and success.
There isn't much to learn about Arsenal at the moment, such is the lacklustre performances on a regular basis, but there were four things that specifically caught the eye at the City Ground.
Mertesacker is better off retiring now
Arsenal's captain hasn't had the most glittering of careers but he has always had a way to defy his doubters and critics. In his last FA Cup match against Chelsea in the 2017 FA Cup final it was perhaps one of the best performances of his career. However fast forward to the Gunners' defence of the famous trophy and the big German had quite possibly the worst display we've seen from him.
Mertesacker is a World Cup winner, a man with 104 caps for his national team. However he looks like a player who is ready to hang up his boots now, rather than at the end of the season. He may have got on the score sheet against Forest but his defensive display was close to embarrassing and provided evidence of why Arsenal need defensive reinforcements quickly.
You can have all the experience in the world but when your time's up, your time's up, and that is the case with Mertesacker.
The German struggled significantly against Brereton, a player at the opposite end of his career at just 18 years old, as he caused him problems all game with his ability to run in behind.
Mertesacker had a good head start on him on a number of occasions but Brereton was always first to the ball. We know he isn't blessed with great pace but this was a potential career finishing performance.
Rob Holding's development has halted
Mertesacker's defensive partner Holding didn't have the greatest of games either, following on from what was a pretty unconvincing display from the young centre half in midweek against Chelsea too.
Holding arrived at Arsenal with little reputation, and at a snip price of a reported £2.7m. For that fee you can't expect much, but his performances in his first season showed signs of a player with excellent potential. However like many young players at the club he seems to be struggling to realise that.
He is still only 22 years of age but Holding's development this season hasn't progressed at all, and it's been hard to progress with the types of players he's been playing with. He's been relatively untested at times in the Europa League and when it's come to games that mean more, such as those in the Premier League and in particular against Forest on Sunday he's looked exposed.
However that isn't necessarily his problem. It's Wenger's problem, and it's the coaching staff's problem. In recent years the club have had a weird way of managing their younger players, and Holding is the latest example of this.
Wenger's touch line ban is no surprise
Today's game marked the first of a three match touch line ban for the Arsenal manager and with another controversial decision going against his team is it any real surprise to see why he is so angry about the state of officiating?
Much has been discussed about the use of the video referral system (VAR) and we'll see it in action when Crystal Palace face Brighton on Monday night. However Sunday's game would have definitely been improved with the use of it. VAR has it's flaws, but in particular incidences such as those in the clash against Forest and Arsenal it would have been particularly useful.
The decision to award the home side a penalty for Mathieu Debuchy's challenge on Armand Traore was the main talking point. Arsenal were just coming back into the game when the Frenchman's tackle was deemed a penalty. The right back did take some of the ball, but then he also came in from behind.
Football is a game of opinions, and like Hector Bellerin's challenge on Eden Hazard in Arsenal's 2-2 draw with Chelsea, even the use of VAR may have made the decision a difficult one.
However there was more controversy to follow. Did Dowell touch the ball twice? If he did then the penalty would not have stood. As he ran up to the ball he slipped and may have hit the ball with both feet.
Even with replays it was difficult to tell whether he did or not though and the use of VAR in that situation may have led to a lengthy stop. But at such a crucial point in the game there is an argument for it to be in place.
The point remains though that Arsenal have conceded four penalties in three games. Much of that is down to rubbish defending, but poor officiating can be argued for three of those decisions to award a spot kick. It's therefore easy to see Wenger's frustrations and it's unsurprising that he was given a touch line ban for speaking out when incidents like those at Forest happen.
Theo Walcott's day's remain numbered
For the slice of misfortune Arsenal perhaps received on Sunday their overall performance was woeful. The defence as discussed before were a mess, but the attacking display was of huge concern too.
Welbeck got himself a goal in what was otherwise a nothing performance, whilst Alex Iwobi's game was also a disappointment. Walcott was the biggest let down of all three of Arsenal's attackers though.
For a player who was one of the most experienced heads on the pitch his performance was pathetic. It may seem harsh but Walcott's days at Arsenal should be done and the club need to be actively looking at getting rid of him this January.
Against Championship opposition he struggled to look threatening and didn't create any openings. His game being summed up by a scuffed effort into the turf when presented with a goal scoring opportunity after seven minutes.
Walcott arrived in North London as a bright prospect, a player destined to become an England regular. But 396 games and 108 goals later he simply hasn't lived up to his potential.
400 games for the club would be a fantastic milestone but if the club have any sense he shouldn't be allowed to get there.