Arsenal lost 3-1 against Manchester United on Saturday, as the Gunners failed to take advantage of an opportunity to solidify a top-four place.

Instead, Arsenal dropped down to fifth, thanks mostly to an early comedy of errors at the back.

But what did we learn from the performance?

Koscielny, Mustafi and Monreal aren’t an unbeatable trio

Going into the match there was a lot of talk about the unit the three defenders were forming, with clean sheets in almost every match they’d played, even against Chelsea and Spurs.

However, this time around, they were pretty terrible.

Koscielny gave the ball away for the first goal, and Monreal abandoned Valencia to close down Pogba (who was already marked by three other players).

Then for the second, Mustafi ignored Nacho’s advice to pass back to Čech, lost the ball, then brainlessly charged out to close down Lukaku, before getting injured.

For the third, Koscielny was too easily outmuscled, and Monreal was nowhere to be seen.

All avoidable individual errors.

De Gea is a top goalkeeper

Many of us had already grudgingly accepted this, but those that hadn’t would’ve found it difficult to watch Saturday’s game without changing their opinion.

He claimed the Premier League record for saves in a single match (since stats started being recorded in 2003) with a number of point blank stops when the Gunners looked destined to score. De Gea was on top of his game. Against most other keepers Arsenal could’ve won the match.

Lukaku is just as bad in big games as we thought he was

I’m not sure exactly what Lukaku did for 90 minutes on Saturday. He was fouled by Koscielny late on, and was gifted the ball in the build up to the second goal, but other than that his most telling contribution was almost scoring an own goal.

In a match where United had a two goal lead for 65 minutes, Romelu couldn’t even make himself useful as an outlet on the counter.

58% pass accuracy and zero shots sums it up pretty well.

His team may have won the match, but the part the Belgian played was minimal at best.

Lacazette, on the other hand, is quality

Arsenal’s striker was one of the Gunners’ best performers on the day.

He scored one, and it was only De Gea’s fantastic keeping, plus a bit of bad luck, that stopped him getting more.

He had seven shots, all of which were either blocked or saved (i.e. none of them were wide of the target).

Laca hit the bar, and should have had a penalty or two as well.

In all, it was just the kind of big game performance you want from him, and it was just unfortunate the defence let him down so badly.