Arsenal's January signings highlight failures of past windows

Arsenal finally got things right in the January transfer window. Their two new signings, Pierre-Emerick Aubameyang and Henrikh Mkhitaryan, made an immediate impact and have given the club a massive boost heading into Saturday's crucial North London derby against Tottenham. But that also highlights just how unsuccessful they have been in other recent transfer windows.

After Mesut Ozil's signing in 2013, it's hard to find many players who joined the club who can be considered a success.

Petr Cech and Alexis Sanchez did well, but the Chilean left the Emirates last month -- in part because he was so frustrated with the lack of top-class reinforcements. And a look at Arsenal's likely starting XI at Wembley on Saturday certainly backs up his case.

Aside from Aubameyang and Mkhitaryan, the expected XI against Tottenham includes just two outfield players signed after 2013: Granit Xhaka and Shkodran Mustafi. And that pair can arguably be considered the two weakest links in this Arsenal side. Tellinly, the club's biggest need this upcoming summer is to sign a centre-back and a holding midfielder -- the two positions that Mustafi and Xhaka were meant to address.

Alexandre Lacazette and Sead Kolasinac initially looked like terrific signings after joining last summer, but they were both on the bench in last weekend's 5-1 win over Everton and should remain there unless Wenger decides to revert to a back-three against Spurs with Kolasinac at wing-back.

Arsenal spent a club-record £110 million in the summer of 2016, then broke the single transfer record on Lacazette last year, only to break it again on Aubameyang last month after the Frenchman's form dipped dramatically in recent weeks.

With the last four years' worth of business looking a bust, Arsenal needed to take drastic steps to address their incompetence in the transfer market, bringing in Borussia Dortmund's chief scout Sven Mislintat and Barcelona's former sporting director Raul Sanllehi in a major backroom reshuffle.

Both played a big part in bringing Aubameyang and Mkhitaryan in and some success was much needed. Here's a look at the outfield players Arsenal have signed since the summer of 2014, and how they have fared (grades are from 1-10, based on how they have performed in relation to their price tag.)

Summer 2014

Alexis Sanchez: Great signing, obviously, and a world-class player when at his best. But the lack of top talent around him was part of the reason he left. Grade: 8/10.

Calum Chambers: Still hasn't justified his price tag of around £16m, which at the time was the most Arsenal had ever paid for a defender. Versatile and he could still develop into a starter, but time is running out. 4/10.

Danny Welbeck: Injuries have ruined two seasons for Welbeck, and he's been too inconsistent when fit. Great work rate, but still not a proper scoring threat and doesn't have a natural fit in the team. 6/10.

Gabriel Paulista: Was a backup for three seasons and was sold just when it seemed he'd found a good fit in a back three. 5/10.

Mathieu Debuchy: Arrived as a replacement for Bacary Sagna but lost his starting place to Hector Bellerin after suffering a shoulder injury halfway through his first season. Arsenal struggled to offload him before letting him join St Etienne on a free transfer last month. 3/10.

Summer 2015

Petr Cech: At £11m, a snip from Chelsea. He has secured a wobbly backline and saved the team plenty of points. But at 35, his best days are behind him. 8/10.

January 2016

Mohamed Elneny: Signed as injury-cover for Francis Coquelin and has never been a regular starter. A decent player, but far from the top-class holding midfielder that Arsenal need and the club reportedly tried to sell him to Leicester last summer. 5/10.

Summer 2016

Granit Xhaka: The Switzerland international was billed as the tough enforcer that the team had been crying out for, but it quickly became apparent that he was much more of a deep-lying playmaker than a ball-winning holding midfielder. His defensive awareness is downright poor, and he simply hasn't lived up to his £35m price tag. 5/10.

Shkodran Mustafi: By far the most expensive defender Arsenal have ever signed at around £35m, and yet the club were willing to let him leave last summer after just one season at the Emirates. However, a move to Inter Milan fell through and he has mixed stellar performances with glaring mistakes this campaign. 6/10.

Lucas Perez: The Spanish striker seemed like a desperation buy after Wenger missed out on his top targets, and that impression was only strengthened when he couldn't get any playing time. Perez made the most of the few chances he got, but it was clear he was never part of Wenger's plans and he was shipped back to Deportivo La Coruna on loan after one season. 4/10.

Rob Holding: Considering he only cost £2m from Bolton, Holding has to be considered a successful signing. But he's still not ready to be a regular Premier League starter and his passing ability remains a weakness. 7/10.

Takuma Asano: An odd signing at the time, and it seems likely the Japanese forward will never play a game at the Emirates. Has spent two seasons on loan in Germany, and won't beat Aubameyang or Lacazette for a place in the first-team anytime soon. 2/10.

January 2017

Cohen Bramall: This one raised some eyebrows as Arsenal signed a non-league defender for around £40,000. Clearly just a low-risk punt on a young left-back with exceptional athletic abilities that could yet pay off. But not a serious attempt at immediately strengthening the first-team. 5/10.

Summer 2017

Alexandre Lacazette: Undoubtedly a very good player, but the French striker has gone from celebrated club-record signing to bench warmer in the span of seven months. Arsenal didn't spend £46.5m on him to be a backup, but Wenger seems to have little interest in playing Lacazette and Aubameyang together. 6/10.

Sead Kolasinac: Snapped up on a free transfer, the Bosnia and Herzegovina international looked quite the bargain when he made an immediate impact as a forceful wing-back. However, Wenger doesn't seem to trust him in a back four (despite having been voted best left-back in the Bundesliga), which has seen him drop to the bench in recent games. 7/10.