Lionel Messi: Club World Cup triumph proves Barcelona are 'best in the world'

Lionel Messi declared Barcelona are the "best team in the world" after becoming Club World Cup champions with a 3-0 win against River Plate in Sunday's final.

Messi, 28, returned from a kidney issue to start the game in Yokohama against Copa Libertadores champions River, and opened the scoring after 33 minutes with a fine finish from Neymar's header down.

Luis Suarez scored twice more after half-time as Barca added a fifth trophy to the Champions League, La Liga, Copa del Rey and European Supercup titles already won in 2015.

This final against River was a special game for Argentina captain Messi, who as a 12-year-old might have joined the Buenos Aires club, but instead ended up in Europe as the Camp Nou outfit were better able to pay for the $900-a-month hormone therapy he then required.

The Rosario-born player told reporters after the game that the main thing had not been beating River in such a showpiece game, but proving that Barca were the world's best side.

"It is special, but not because we have played against an Argentine team," Messi said. "It is because it shows we are the best team in the world."

Messi had missed the 3-0 win over Guangzhou Evergrande due to a kidney problem, but having passed a stone in the meantime, was passed fit to start the game.

"The truth is I felt a very ugly plain, but thankfully I have recovered and I felt good during the game," he said.

Messi had already scored in each of his three World Club Cup finals -- the extra-time winner against Estudiantes in 2009, a double in the 4-0 stroll past Santos in 2011, and now the opener in 2015.

The 28-year-old forward and Blaugrana club captain Andres Iniesta have now won a record 26 career club trophies, passing the mark of 25 set by former teammate Xavi Hernandez -- but Messi said he was still hungry for more medals.

"We are very happy," he added. "We played a great game and we always have the same objective -- the more trophies we can win the better."