Ian Walton/Getty Images

Lionel Messi currently shares the 2014 World Cup top-scorer mantle with Brazilian favourite Neymar, with Argentina progressing through the group stage in unbeaten form, despite a shaky defence threatening to undo some scintillating attacking football.

However, Antonio Cuccitini, Messi's grandfather, isn't convinced his daughter's son is playing to the best of his ability. Speaking to Channel 3 from Rosario, Argentina, reported via AS, the demanding onlooker is hoping his grandson's game will improve in the knockout stages:

Right now Leo isn't running, I'm not convinced by him. I’m truthful and I don't have time for hot air. I think he’s been pretty poor. In Spain he’s got more zip, he goes round 22 players. He needs to get his spark back. You can't demand everything. He's not God, who can do it all. Praise be that he got the goal against Iran and we've qualified.

Somewhat humorously, Cuccitini concluded by saying, "Keep your chin up, you'll do great, I love you lots."

Jeff Gross/Getty Images

Messi's chin was more than up when he netted a sublime free-kick during Argentina's 3-2 win over Nigeria on Wednesday. The goal was his second of the match and came just minutes after Vincent Enyeama had produced an excellent save from another Messi set piece in a similar situation.

His grandfather's comments provide a frank, and perhaps realistic, assessment of a strange World Cup for Alejandro Sabella's side. Messi certainly hasn't been at his mercurial best, at times lacking intensity on the ball and playing sloppy passes. But without his goals, Argentina would have been seven points worse off in Group F.

Cuccitini is correct in asserting his grandson's overall game hasn't been as intricate, decisive or consistently impressive as his performances at Camp Nou, but that is regularly the case on the international stage.

World Cup progress isn't always secured on the replication of tremendous club form, but it is usually defined by moments of magic by top players. Messi's overall game may be slightly off the boil, but his ability to make a difference is as impressive as anything else shown at the tournament thus far.

Miguel Delaney of Eurosport lists the problem with Argentina's set-up: Sergio Aguero's injury, the lack of form shown by Gonzalo Higuain and formation uncertainties that threaten to see the side beaten. Despite all of this, Delaney highlights Messi is the main story:

All of that should be the dominant story, the decisive factors. And yet, it's impossible to not return to the main issue, the main man: Messi. What's more, far from the 3-2 win over Nigeria casting more light on their deeper problems, it only re-asserted his importance. It made the Messi narrative all the more relevant. He is getting better.

Getty Images/Getty Images

The 27-year-old is just one strike away from equalling Diego Maradona's haul of five at the 1986 World Cup, the last time Argentina captured the trophy.

While there's plenty of improving to do across the board if such a triumph is to be repeated, few would bet against Messi breaking his predecessor's total during the round-of-16 tie with Switzerland.

Messi is finally delivering on the World Cup stage, something many detractors have held against him since he shot to prominence with Barcelona a decade ago. His overall performance may be slightly off, but if he keeps scoring goals, he won't care one iota.