If one player could sum up Manchester United’s topsy-turvy season at the moment it’s Paul Pogba, who went from the sublime to the ridiculous in the space of four days.

At the same end that the French World Cup winner set up Mason Greenwood for United’s opener against RB Leipzig in Wednesday's barnstorming 5-0 Champions League victory, he brought down Hector Bellerin in Sunday's Premier League clash against Arsenal - a ludicrous challenge which led to the Gunners converting a penalty and taking all three points in the league at Old Trafford for the first time since 2006.

“We know it's a poor performance. Myself, I cannot give a foul away like this. I thought I would touch the ball but I didn't. [I] cost us the goal today with the penalty. We have to do better, the team, myself, it starts with me,” Pogba told the BBC.

"Maybe I was a bit out of breath, it made me do this stupid mistake. I will learn from that, I'm not the best defensively in the box, I can work on that.”

The admission from Pogba that he was possibly 'out of breath' is a shocking one to make considering it was only the 68th minute of the game. Manager Ole Gunnar Solskjaer had legislated for his ordinary early season form due to a positive diagnosis for Covid-19 but, after a dominant display on Wednesday in Europe, he can’t hide behind excuses any longer.

Pogba held his hands up at full-time and admitted guilt on the goal but conceding the penalty wasn't the only problem. Despite playing on his favoured left-hand side, as Solskjaer set up with a diamond in midfield for the second consecutive fixture, he struggled to have an impact on the game.

Meanwhile, Arsenal’s landmark midfield summer signing Thomas Partey and Mohamed Elneny ran the show for the visitors. As United’s diamond lacked any kind of sparkle, those two shone bright with Partey in particular dictating a dominant Arsenal display.

The Ghanaian’s driving runs forward created opportunities for the visitors - exactly the sort of contributions United could have done with from Pogba, Fred and Scott McTominay - but Solskjaer’s side failed to make any impact in the final third.

“I thought he was outstanding,” former United captain Roy Keane told Sky Sports when asked about Partey’s performance. “We said before the game, this guy’s no mug, he’s played for a big club, he’s played in big competitions.

“We saw today, when you watch a player live, that’s when you can judge a player. The more I look at him the more I wish he was in Man Utd’s midfield.

“Big, strong, aggressive, obviously going back with Arsenal I had my battles with Patrick Vieira, I think this kid has got a chance of matching what Patrick used to do.

"He’s big, he’s strong, he’s aggressive and he likes to pass it forward. He can deal with the ball, he looks comfortable on the ball, just small little details, composure, good first touch, retaining possession, that’s the name of the game.”

The qualities listed by Keane were exactly what was missing from United’s midfield as they put in another poor performance at Old Trafford. Three home defeats and a solitary goalless draw make for grim reading for Solskjaer when he considers his side's Premier League form so far this season.

Fred was playing as the deepest holding midfielder in the diamond, to provide cover for the back four, but United could have done with the Brazilian - along with Pogba and McTominay - picking the ball up and driving forward as Partey did for Arsenal.

The 27-year-old, signed from Atletico Madrid on deadline day, was superior to all of United’s midfielders in all aspects. He was calm, commanding on the ball and showed great vision and awareness.

Everything United would have hoped for from Pogba, Partey delivered for Arsenal. There were the 11 recoveries to Pogba’s six, a 94 per cent passing accuracy in the opposition half compared to Pogba’s 76% and Partey won 10 duels to Pogba's four while the Frenchman lost 12 of his duels compared to Partey's four.

Solskjaer suggested afterwards that without Pogba’s ridiculous challenge in the box it would have likely played out to a goalless draw. However, despite costing his side, Pogba should not be the scapegoat for another home defeat.

While the midfield clicked and powered the victory against Leipzig on Wednesday, to a man they floundered and panicked under the Arsenal press - losing possession and failing to build attacks.

Pogba wasn’t the sole problem, but he was part of it. Now it’s back to the drawing board for Solskjaer as he looks to get his diamond shining again.