For many, Lionel Messi is the greatest player of his generation. For others, he is the best of all time.

And yet for all of his greatness, Messi has a problem. Not a major one, mind you, but certainly a concerning one for a player who knows how to score at will. This season alone he has more goals from open play than anyone else. He is also an elite passer and undoubtedly the most well-rounded attacker in all of soccer.

But Messi has a problem when it comes with being one on one with the keeper from the penalty spot. He doesn't have a horrid record mind you, but in recent years it has become an area of weakness. Where once some perceived him as automatic from the spot, many question whether he will make it happen.

And even Messi himself is noting that there are some issues.

"Yes there is a lot of frustration that I have missed a lot of penalties, both for the club and for Argentina," Messi said according to Barca's official magazine. "I am the designated penalty taker, but when the goalkeepers study you they know your ideas more. It is true to say that a well-taken penalty is very difficult to stop, but now it's more complicated when it comes to taking a penalty.

A lot has been made of how the superstar has changed his approach. Where he once waited for goalies to make their move first, he has now become more dependent on picking his spots and sticking with the decision. The results have been mixed at best with Messi's miss against Manchester City becoming one of the most high-profile examples of his career.

Since 2009, Messi has scored 37 penalties and missed six, good for an 86 percent conversion rate; Ronaldo meanwhile has 52 penalty goals in 58 tries (89.6 percent). That margin was a lot wider in late February when Messi's conversion rate was at 85 percent but he has scored in three straight attempts to alter that number.

That said, the superstar is getting a lot of criticism because of those six misses, two of them have not even been stopped by the keeper. Earlier this season, Messi missed two penalties, one for club and another for country, both of which were heavily criticized.

Ronaldo meanwhile, despite failing on the same number of penalties has never actually missed the target in that span.

One interesting note is that Messi scores and misses many of his penalties in the same area. A chart from WhoScored.com in February showed that Messi scored 12 of his 34 attempts up to that point in the lower left corner. But of his six misses, four of them came in that same exact area.

With the Champions League entering its most important stages, Messi could find himself up at the penalty spot in a game situation or even in a major shootout at the end. And if he is in that situation, he needs to know that he has the confidence to get the job done.

His words indicate a man in a bit of a rut, but he has been solid in his last three attempts and there is no reason why he can't continue improving in big games.