Christian Cueva was not always so important to Peru. For two years prior to the arrival of Ricardo Gareca, the country's long-haired Argentinian coach, Cueva had not been called up. He did not earn a cap. He was frozen out and, it appeared, forgotten.
Now, though, he is an integral part of Peru's plans. Had striker and captain Paolo Guerrero's ban not been overturned, it could have been argued that Cueva, a technically gifted, creative attacking midfielder, was the key to Peru's hopes of success in the World Cup.
Even with Guerrero available, Cueva's form will be crucial. He is the link between midfield and attack, the primary playmaker in a functional, organised team. He will bring a necessary guile.
Club form has been impressive
For the last two seasons, Cueva has played his football in Brazil with Sao Paulo. There he has impressed, although the consensus at club level is that he is inconsistent: a talented footballer with enviable ability but one whose temperament can prove a hindrance.
There is an expectation that Cueva will leave Sao Paulo, perhaps for Europe, this summer. His argumentative nature, according to onlookers in Brazil, has caused him problems: Cueva reportedly fell out with Sao Paulo coach Diego Aguirre and the club are now actively searching for a replacement.
Frustrations have been added to by Cueva's apparent disregard for discipline. He has been known to skip training and did so after Peru secured qualification to the upcoming World Cup with a playoff victory against New Zealand. He had been out celebrating.
His commitment cannot be questioned
For many, though, Cueva's extravagances can be tolerated. Particularly those of a Peruvian persuasion. His attitude has not been such an issue when donning the red and white shirt. His commitment will not be in question.
And there are plenty who believe reports of wrongdoing and ill-discipline are hyperbolic, exaggerations. "It's all overblown for me," Austin Miller, a journalist covering Brazilian football, tells RealSport. "He's hard-nosed and cares."
Of that, there is little doubt. A fully focused Cueva is likely to be a real threat for Peru's opponents in Group C of this summer's World Cup. His ability to operate in tight spaces, to create chances from different areas of the pitch, could prove the difference between progression into the last 16 and a premature exit.
"Gareca is absolutely confident in Cueva," Víctor Zaferson, a Peruvian journalist, tells me. "When Cueva is focused Peru work perfectly. They depend on him to create opportunities for Guerrero. In Russia, he has to show all his ability."
It has not always been this way. While at Spanish club Rayo Vallecano - Cueva's only experience of European football thus far - and later Club Alianza Lima, between 2013 and 2015, he endured a difficult period of rejection from his country.
"Cueva has woken up after some ups and downs," says Zaferson. "He had personal problems and he suffered a lot. But now Peruvian fans respect him a lot."
The influence of Gareca has been significant. His guidance, his calming presence, has allowed Cueva to concentrate, and he has excelled. It was evident in Peru's recent friendly victories: a 2-0 win over Scotland, in which he scored a penalty, and a 3-0 defeat of Saudi Arabia. Cueva was a constant threat throughout.
For Peru, he will line up as the number ten in a 4-2-3-1 system, although he has licence to drift. Cueva regularly drops deep to collect the ball, beginning moves with crisp, accurate passes. He regularly moves out wide, too, often joining Peru's three forward players in what can begin to resemble a flat front four.
"He does like to drift to the left flank because Peru like to build attacks from that side - via Trauco and Flores," says Peruvian football expert Peter Galindo. "He can also play as a left winger, which influences that shift."
Peru's next best player
Expect to see Cueva pop up in unexpected areas of the pitch. He is diminutive and stocky, so his presence can often go unnoticed. That is until he wriggles through a disproportionately small gap to assist, or indeed score a goal.
"Outside of Guerrero, Cueva is seen as Peru's next best player," Galindo adds. "He's indispensable, no matter his form, because he's capable of conjuring up chances from nothing."
"He will definitely be key, but Peru is a tightly knit side. They're not reliant on an individual or two. That being said, when Cueva is on form, dribbling past defenders & sending in through balls, it's a joy to watch."
France, Denmark, and Australia will be hopeful that he is not.
Listen to the RealSport football writers discuss Group C in Kremlins in the Basement: RealSport’s daily World Cup podcast.