Ex-Argentina playmaker Juan Roman Riquelme says that the reason his country have not won an international trophy recently is that Lionel Messi "plays alone."
Argentina's last big success was the 1993 Copa America, while their barren run at the World Cup goes back to 1986.
With Messi as captain the Albiceleste have reached the final of both tournaments in recent years, but they lost the 2015 Copa America final to Chile after suffering similar disappointment when being beaten in extra time by Germany in the 2014 World Cup decider.
Asked on FOX Sports why the Barcelona talisman had not yet lifted a trophy with his country, Riquelme said the blame lay with his teammates.
"Because Messi plays alone," Riquelme said. "He is the best in the world. We must look after him. He is Argentine, and I have no doubts that if he is in good form, Argentina will be very close to winning this Copa America."
Riquelme played alongside Messi at the 2006 World Cup, where they exited in the quarterfinals to Germany. The pair then reached the final at the following year's Copa America, only to lose 3-0 to Brazil. They finally shared international success at the 2008 Summer Olympics, both featuring through the tournament as Argentina won the gold medal.
The former Barcelona, Villarreal and Boca Juniors player said he had never seen anyone with Messi's talent or application.
"There is nobody like Messi, not here, or anywhere," Riquelme said. "I am Argentine and I had the good fortune to play with him. He is a marvel. A player who has won so much, who keeps competing every year to win titles, never settles for what he has. People should enjoy him."
Riquelme said he was confident about Argentina's chances at this summer's Copa America in the United States, unless Messi picked up an injury problem.
"I am confident about this Copa America," he said. "Argentina will be closer. They have good players, and Messi is in good form. If Messi does not get injured, we will win the Copa America."