Arsène Wenger lamented the performances of his senior stars as his Arsenal side crashed out of the Capital One Cup in the third-round stage, for the first time since 2002. There were some real positives to take from Tuesday's clash, but what did we really learn from the Gunners' loss to Ronald Koeman's Southampton?

Isaac Hayden could be a star:

Arsène Wenger opted for a blend of youth and experience against Southampton on Tuesday evening. Established stars such as Tomas Rosicky, Lukas Podolski, Jack Wilshere, Alexis Sanchez all featured, but Arsenal’s defence was inexperienced. Young Isaac Hayden made his debut at centre-back alongside Calum Chambers, who was making his first appearance against his former club. Hayden performed very impressively; he was strong in the tackle, composed in possession and didn’t appear overawed by the occasion.

Hayden was up against in-form Graziano Pellè, who had scored three goals in his first four matches, but he dealt particularly well with the imposing Italian. With Arsenal’s lack of defensive options, Hayden may be used as centre-back cover, particularly with Chambers currently deputising for the injured Mathieu Debuchy. The 19-year-old can also operate in the defensive midfield position; therefore his versatility could prove to be invaluable to the Gunners.

Lukas Podolski’s days may be numbered:

Despite Arsenal’s lack of defensive depth, they are blessed with exciting attacking options. Lukas Podolski is one of a handful of senior stars who has had limited opportunities this season, therefore Tuesday’s clash was a perfect opportunity to cement his claim for a regular starting berth. However, the former Cologne star did nothing of the kind. His apathetic display left most Gunners fans exasperated; he has the tendency to be anonymous, but his lack of effort and desire was abundantly clear. His poor-work rate was further exposed by the industry of Alexis Sanchez.

Despite possessing world-class ability, the Chilean has an exemplary attitude and sensational work-rate, the qualities Podolski rarely demonstrates. Whilst Alexis was working tirelessly to regain possession and pressure the opposition, Podolski barely broke into a light stroll.

The experienced German was on the verge of leaving the Emirates prior to Olivier Giroud’s injury, but rather than attempting to prove his worth, he seems completely disinterested. He is renowned as a clinical finisher, but that is simply not enough; he is notorious for his reluctance to track-back and against the top opposition, you cannot have passengers in your side.

When you compare the work-rates of Willian and James Milner, the wide-men for title rivals Chelsea and Manchester City respectively, there is simply no comparison. Wenger had been questioned by many Arsenal fans for his reluctance to start Podolski, but after Tuesday’s debacle, the Frenchman’s judgement has been vindicated. Unless he significantly changes his attitude, a January exit for the likeable but frustrating German, seems inevitable.

Abou Diaby ‘could’ be the midfield-enforcer Arsenal desperately need:

One of the major positives from Tuesday’s defeat was the long-awaited return of Abou Diaby from injury. Diaby was making his first competitive appearance for Arsenal in almost 600 days, but impressed in a deeper-midfield role. He was replaced after 66 minutes as he was inevitably lacking in match-fitness, but he provided a refreshing balance in the Gunners midfield.

Up against Southampton’s combative midfield-duo Morgan Schneiderlin and Victor Wanyama, Diaby coped well and was an invaluable presence in the midfield. He was particularly accomplished on the ball, with Wenger highlighting his intention to deploy Diaby in a holding role. The Arsenal manager admitted: "I try to transform Diaby to a defensive midfielder. Facing the game will be easier than playing back to goal with the injuries he had."

The Frenchman has all the attributes to play in the deeper-role; he’s competent in possession, effective in breaking-up the play, whilst he provides a much-needed physical presence. Arsenal were bullied by Chelsea and Manchester City away from home last year; Diaby’s presence would give Wenger’s side a greater midfield balance and protection for the back-four.

However, Diaby has always been an offensive-minded midfielder. The big question is whether he has the discipline to curb his attacking instincts and adopt a defensive-mind-set. In addition, Diaby’s dreadful injury record is the most obvious concern. The imposing Frenchman has had an astonishing amount of injuries during his spell at Arsenal; if he were to succumb to injury, the North Londoners would be back to square-one. Nevertheless, if he remains fit for a considerable period, Diaby could be the midfield-enforcer that Gunners fans have been yearning for.

Rosicky and Campbell were lacking match-sharpness:

Tomas Rosicky made his first competitive start of the season and skippered the side with both Mikel Arteta and Per Mertesacker rested. Rosicky was way-below par, although he was not lacking in industry. The Czech-Republic star was responsible for Southampton’s equaliser, clumsily tripping tricky Saints debutant Sadio Mane in the penalty area. Rosicky’s ball retention was very disappointing, as he struggled to cope with the frenetic pressing from Schneiderlin, Wanyama and Steven Davis in the Southampton midfield.

The former Dortmund man always attempts to initiate urgency and pace into Arsenal’s offensive play, but his lack of sharpness coupled with his wasteful distribution contributed to a disappointing evening for the Czech. Despite this, his experience and quality ensures he will remain a crucial component of Arsène Wenger’s squad.

Tuesday also saw highly-rated Costa-Rican Joel Campbell make his first competitive start for the Gunners and likewise, he failed to make an impression. Campbell was deployed on the right-wing, but came inside too often to the extent that it became predictable. He lacks the blistering pace of Sanchez and Alex-Oxlade-Chamberlain, so perhaps would have been more effective in the centre-forward role.

Campbell’s hold-up play and movement is more suited through the middle whilst his threat is slightly negated out wide. On the basis of that display, Campbell’s first-team opportunities may be limited, but he certainly has potential. When given his next first-team chance, he must deliver.

Chuba Akpom needs first-team football:

Chuba Akpom is arguably one of Arsenal’s most exciting youth prospects for many years. He’s performed superbly for the U21 side this season, scoring six goals in just four appearances. He is a natural centre-forward; he has excellent movement, natural pace and is a clinical finisher. He was included in the squad for Tuesday’s clash, but was brought on in the 86th minute; so he had no opportunity to make an impression on the game. After Podolski’s apathetic display, most would concur that Akpom would have provided a more dangerous outlet.

Nevertheless, if the young forward had struggled, Wenger would have been lamented for omitting Podolski. It was a tough decision and hindsight is a wonderful thing. Irrespective of this, as a young player, there is no better manager to develop under in world-football than Wenger; he places incredible trust and belief in youth and has a phenomenal record of developing talented youngsters.

However, with the Gunners out of the Capital One Cup, Akpom will surely have very limited first-team opportunities at the Emirates. Many believe that Akpom is more deserving of a starting role than Yaya Sanogo, who has failed to score in 17 competitive appearances, although Wenger is unlikely to abandon the trust he’s placed in the French U21 international.

Perhaps a loan move to a lower-league Premier League side, or even a Championship side, would be beneficial for Akpom. A player of his ability needs regular playing time against competent opposition to develop and gain more experience. Daniel Sturridge, who enjoyed a fruitful loan spell at Bolton, is a shining example of how beneficial a loan spell can be.

He was given a chance to prove himself at the Reebok and just two years later, he is one of the Premier League’s most prolific forwards. If Akpom is given this opportunity to flourish and develop in either the Premier League or Championship, Arsenal could reap the rewards come next season.