To say Arsenal had an eventful January transfer window would be putting things mildly.

Arsene Wenger is notorious for keeping his wallet tightly shut, particularly in the winter, but was buying and selling like it was going out of fashion this month.

Arsenal and Manchester United exchanged one of the biggest and most controversial deals in the recent Premier League history, exchanging Henrikh Mkhitaryan and Alexis Sanchez with the latter's contract six months from expiring.

The Gunners weren't finished there, though, Olivier Giroud was offloaded to Chelsea, Theo Walcott to Everton and Pierre-Emerick Aubameyang was sensationally procured from Borussia Dortmund.

Throw in the fact Mesut Ozil signed a new contract at the club and you have a pretty exhausting start to 2018 at the Emirates Stadium.

Paul Merson delivers verdict on Arsenal's window

However, for all the transactions and money thrown about during January, has it actually paid off the Gunners?

That was a question Sky Sports pundit Paul Merson tried to work out as he traipsed through all 20 Premier League teams and assessed their January spending. 

Merson is often criticised for his questionable preparation and predictions, but you have to say that the 49-year-old has knocked it out the park on this occasion. Even the alphabetical ratings he gave to the Gunners sum it up perfectly.

Lack of defensive reinforcements 

The Arsenal legend penned: "Arsenal: A for attack, D for defence.

"I'll give them an A for attacking because Aubameyang and Mkhitaryan are top, top-drawer players.

"They've lost Giroud but getting rid of Walcott was good business in my opinion. But they've brought in no defenders and they need a centre-half. How have they not got Jonny Evans out of West Brom?

"I was watching the game against Swansea thinking: 'You're going to pay £60m for another centre-forward when you've already got a £40m forward in Lacazette, who isn't going to get a game now?' I'll give them a D- for defensive work."

You'll struggle to find an Arsenal fan complaining about the Aubameyang signing but could it have been better spent on a defender? When you look at the Swansea City performance, you really have to wonder.

Gooners can only hope that the quartet of Ozil, Lacazette, Mkhitaryan and Aubameyang is enough to counterattack those lingering problems in defence.

Do you think Arsenal have gone about their business wisely? Have your say in the comments section below.