Lionel Messi's injury is another setback in what has already been a challenging start to life at Paris Saint-Germain. 

The six-time Ballon d'Or winner will be missing for PSG in a key clash against RB Leipzig tomorrow, with discomfort in both his left hamstring and knee.

The talismanic Argentinian has endured a tough start to life in the French capital, failing to score in Ligue 1 so far but netting three times in the Champions League.

There is no denying that he has not carried his magic across the border since departing Barcelona and his lack of influence is becoming a worry for fans.

Below we take a look at Messi's struggles during the current campaign, and what he needs to do to recapture his best form.

New surroundings

There is not a person on the planet who will criticise Messi's ability and talent when a football is at his feet. 

Yet, with the 34-year-old having spent the entirety of his career at Barca, it is understandable that the magical forward is taking time to adapt to the playing style of his new league.

Ligue 1 is well-known for its physicality, with plenty of teams looking to impose themselves on matches — especially when they are playing against some of the world's best talents. 

PSG have faced opponents keen to disrupt their rhythm and have found it hard work to win games — five of their 12 league matches have been secured by just a one-goal margin.

Les Parisiens have struggled to discover attacking fluency and Messi has often been reduced to finding space in less-dangerous areas of the field.

Big fish, big pond

Another issue that could be influencing Messi's performance is the overload of superstars that exist within the PSG squad.

At Barcelona, Messi was head and shoulders above the rest — he was undoubtedly the best player at the club and would take centre stage every time he stepped out at the Camp Nou.

In Paris, he has competition in the form of Neymar and Kylian Mbappe.

This has certainly had an effect on the four-time Champions League winner's output.

Mbappe has provided the majority of goals between the front three, scoring five times in his 11 league appearances and also registering four assists.

Messi has tried to exert his influence — totting up 15 shots so far in Ligue 1, but only four of them have hit the target.

If you also consider Neymar's influence, it is easy to see why Messi's stats are limited this season. 

Coach Mauricio Pochettino stated earlier in the year: "We're not a team yet. We are a club that has recruited many players this summer. There are some big names but we have to turn into a team."

This suggests that despite the difficulties the front three at PSG have had so far, Pochettino has faith in his players and believes they will click sooner rather than later.

Unable to settle

Another issue that will have impacted Messi on the pitch is the constant disruption to his playing time, and lack of a pre-season.

Messi did not sign with PSG until August 10, by which point the club had already played their first domestic game of the season.

A lack of pre-season has an impact on any elite player, even Messi — he did not make his debut for PSG until the end of August against Reims.

Former Marseille striker Djibril Cisse has defended Messi's poor form and puts it down to numerous different reasons.

The ex-Liverpool man said: "Messi's problem, if we can speak of a problem, is that he's a human being. He has emotions. He has lifestyle habits.

"For more than 20 years, he was in his element in Barcelona. We take him, we put him in another environment and we say to him: 'Go ahead, perform.'"

Soaking up the pressure

Despite confirming his wish to return to Barcelona as a sporting director in future, for now, Messi remains focused on returning to form for his current club.

His boss certainly has no doubts that Messi will be back to his best before long. 

After his signing in August, Pochettino said: "Since he arrived, he has really adapted very quickly and he’s been training very well, trying to achieve his highest level as soon as possible."

Messi has still produced moments of magic for PSG this season, largely in the Champions League.

It could be a case of firing on all cylinders once he grabs his first goal in the league.

We all saw just how good he was when he partnered with Neymar previously. It is more than likely that he will click with the Brazilian — and Mbappe — in Paris too.

One thing is for sure, Messi has proved his doubters wrong every time.

There is no reason why he will not rule the world once again.