COMMENT: Well, it's now confirmed. Arsene Wenger has lost his marbles. He's loony tunes. And the proof is what we saw at Old Trafford on Sunday.

A striker and a defensive midfielder. That's what Arsenal need to be champions. A 20-goal a season striker and an experienced, ball-winning midfielder. That's what the Gunners require. It's so, so obvious. Clear as the Manchester weather on Sunday. But not according to Wenger.

Albert Einstein could've been talking about the Arsenal manager and his transfer policy when he stated: "Insanity is doing the same thing over and over again and expecting different results". Remind you have anyone, Gooners?

You have to have some sympathy for Arsenal fans. Particularly those who made the sorry trip to Old Trafford. Yeah, talk of a lack of desire; a lack of passion from the visitors is legitimate. Bottlers is the right description. But this utter, utter humiliation - which is what it was no matter how the scoresheet reads - was created inside Wenger's office at London Colney.

He actually went into the game confessing concern about their lack of goals... no, really, he did. The Frenchman, upon the closure of both transfer windows this season, had dismissed the calls for the need of a striker signing. But going into Sunday, there he was, admitting concern over both Alexis Sanchez and Oliver Giroud's goal scoring form.

And Ander Herrera's winner for Manchester United exposed the frailty of Wenger's midfield. The Spaniard was allowed to run from inside his own half, unchecked, before meeting Marcus Rashford's lay-off to score United's third. Coquelin was nowhere to be seen. And five minutes later? Wenger hauled him off to throw on the untried Mo Elneny. This was no tactical change. It was like-for-like. Wenger hoping the Egyptian could offer a step up from what Coquelin had produced.

Over at Leicester City, the Premier League leaders won thanks to a late goal from a striker held much in reserve this season - Leo Ulloa. And Gokhan Inler, the Switzerland captain, couldn't even make the squad for the Norwich City game.

For the Gunners, it didn't have to be like this. But bottling the title - and in such a crazy season - is of their own making.

In a week when Arsenal announced cash reserves of £160 million, they've blown their Champions League campaign at home and also their League hopes at a patched-up, jack-of-all trades United. It was only a week ago this Arsenal team was being likened to the Invincibles. Now, today, they're staring at the genuine possibility of finishing the season - this crazy season - potless. Second best to Leicester City.

At the final whistle on Sunday, Wenger urged Arsenal fans to "stay positive". He refused to question his players' desire nor commitment and also would not single out any for criticism.

But this was humiliation. Where United had one, experienced defender in their back four, Wenger had the luxury of naming Per Mertesacker on the bench. You can count the number of U21 starts Rashford has had on one hand, yet he made mugs of Gabriel Paulista and Laurent Koscielny. A double and an assist on your Premier League debut? Incredible.

The 3-2 scoreline suggests Arsenal were in the game. They must have been - Wenger said so.

But United always had Arsenal's measure. By the end, Memphis Depay was dragging a high ball down with his heel and Guillermo Varela was mocking Nacho Monreal, flicking the ball over the visiting fullback's head. This time last year, Varela was playing against kids and semi-pros for Real Madrid Castilla. On Sunday, after a shaky start, he stared down Alexis and finished the game taking the mick out of Monreal.

For United fans, it was one of those special days. The kids had Old Trafford rocking and even inspired Louis van Gaal to make a first appearance - and then a second - on the touchline.

Arsenal's players. The would-be champions. Were outplayed and outfought by a United team with barely a playing CV between them.

There was a telling moment from Rashford, just before his substitution, that summed up how United performed on Sunday. Memphis had darted in from the flank and smacked his shot straight at Petr Cech, who fumbled before collecting the ball at second attempt. As Cech moved to clear, you could see Rashford thumping his sides, castigating himself for not gambling on Cech dealing with Memphis' drive cleanly. The teen was desperate to play - like everyone at United on Sunday - without regrets.

Which is all Arsenal will be left come the end of this season.

NOW WATCH THE ODDBALL FLY

Now watch the oddball with the hat and Rolls fly.

Memphis Depay, fresh from a five-star performance against FC Midtjylland, went into Sunday wearing a stinging barb from Ruud Gullit.

Those inside United felt the FCM display was a turning point for the winger, but Gullit wasn't so sure, branding his fellow Dutchman "an odd character in a hat with a Rolls Royce".

But Memphis was outstanding against Arsenal and appeared to relish the responsibility of being a senior player in a patched-up United team.

The slalom runs from left to right were still there. But he also tracked back, keeping Hector Bellerin's threat minimal and his hold up play was critical at key stages as Arsenal attempted to find a way back with their possession game.

Forget FCM, it was Sunday, on the biggest stage, where Memphis, for the first time, lived up to his reputation. The doubts will be gone and the confidence levels sky high. By the end of the 90, he was showboating, taking the mick out of Arsenal's players.

It's one performance. But it was a performance against the best the Premier League has to offer. Memphis now knows he can live in such company.