Arsenal's FA Cup humiliation showed biggest weakness Mikel Arteta must address

The FA Cup has been a safe haven for Arsenal over the years, but the old competition may well have plunged Mikel Arteta into further scrutiny.

Arteta brought himself plenty of leverage when he won the historic competition in 2020. His success over Frank Lampard's Chelsea at Wembley appeared to be his safety blanket when Arsenal's results began to suffer in his first full season in charge of the north Londoners.

However, the familiar daggers could soon be out to get him once more after Nottingham Forrest shocked the Gunners 1-0 at the City Ground.

Lewis Grabban's 83rd minute strike was enough to send Arteta and his beleaguered side tumbling out of the competition.

While Arteta named many of his biggest cannons against Steve Cooper's determined men, Arsenal's secondary weaponry let them down against the Championship side.

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Arteta's dropped the jaws of every person in the City Ground when he hauled summer signing Nuno Tavares off after 35 minutes, while Arsenal youngster Charlie Patino was also swapped for Alexandre Lacazette after 69 minutes.

The 18-year-old certainly appears to be a bright prospect, but he struggled with the intensity and aggression of the cup contest - better days are ahead of the Arsenal academy star.

Most of the sentiments accompanying Tavares' start to life at Arsenal, since his summer move from Benfica, have been ones of promise and positivity, but the look of fury and his throw of the gloves proceeding his substitution could see him suffer the wrath of Arteta.

The Arsenal boss has assembled a young, vibrant, and impressive young team, but his side wilted without the presence of their wiser heads.

Thomas Partey and Granit Xhaka's rock-solid partnership was a huge miss for the Gunners, while Eddie Nketiah rarely troubled the Forrest back four.

Unfortunately for the Gunners, their lack of squad depth will continue to hamper their top four and title aspirations if it is not addressed.

Arsenal's brilliance in recent weeks has made their horrific start to the Premier League season feel like a bad dream. Unfortunately, a dream it was not, and Arsenal cannot afford to treat it as such.

Their early squad depth issues were completely exposed in their 2-0 defeats to Brentford and Chelsea, before Manchester City pulverised them into the turf in the following encounter.

Arteta's side have certainly turned a corner since that hideous day at the Etihad Stadium, and their performance with ten-men against Pep Guardiola's side was testament to their vast improvement.

Patino's immersing with the first team and his start against Forrest suggests he will very soon become a huge part of Arteta's squad, while the same can be said of summer signing Albert Sambi-Lokonga.

But their alternative options in the defensive areas are posing even more difficult questions.

Gabriel Magalhaes' absence always sticks out like a painfully sore thumb, while Cedric Soares is a completely different defender to first-choice star Takehiro Tomiyasu.

Tomiyasu has proven to be an exceptional piece of business since his £15.5m arrival from Bologna, solidifying the right-side of the Gunners' back-line with his intelligent positioning and no-nonsense approach to defending.

Unfortunately, the same cannot be said of Soares, who only seems to come alive when he is given the opportunity to maraud forward and join the attack.

Arsenal's alternative options in the squad are neither equal in quality nor are they like-for-like in style.

Very few teams can replace one top player with another top play of equal ilk in the Premier League, but the top teams can compensate for the absence of their star men with players who at least possess similar traits, strengths, and playing styles of the absent star.

This is currently not the case at the Emirates Stadium, and if Arteta's side fail to overcome Liverpool in the League Cup semi-final, Arsenal will not have any more safe havens left to cushion their fall.