The Spanish giants welcomed back Messi after a bout of kidney stones and the mercurial Argentine scored with a clinical finish on 36 minutes, before a lethal Luis Suarez double destroyed River’s hopes.
“We came here to win the title and it was important to get the job done,” said Suarez, who picked up the player of the tournament and golden boot award after finishing with five goals.
“We stayed calm and played our game until Leo scored the first goal. More than my goals, it was just important to get our hands on the trophy.”
Neymar, himself returning to the side after a groin strain, was instrumental in Barcelona’s opener, climbing to knock down a Dani Alves cross for Messi to steer past River goalkeeper Marcelo Barovero with a deft flick of his left boot.
Suarez, who scored a hat-trick in Barca’s 3-0 semi-final win over Guangzhou Evergrande, scored a second with a fierce low drive four minutes into the second half.
The former Liverpool striker grabbed his second of the night when he dispatched a thumping header past Barovero after a pinpoint cross from Neymar.
River Plate’s starting eleven cost a total of some six million dollars, while Barcelona paid $85 million for Suarez alone, and the gulf in class showed.
The Catalans, who had already collected the Champions League, Spain’s La Liga, the Copa del Rey and European Super Cup this year, tore River to shreds in the second half. Neymar also came close to scoring with a curling effort that shaved the bar.
Barcelona goalkeeper Claudio Bravo was a spectator for much of the game on a cold night but made an acrobatic save from River substitute Gonzalo Martinez seven minutes from time to deny the South Americans a consolation goal.
Messi, who forced a smart save from Barovero in the early skirmishes and could himself have finished with a hat-trick, became the first player to score in three finals after leading Barca to victory in 2009 and 2011.
“Messi and Neymar wanted to play in the final, no matter what,” said Suarez. “It shows the sacrifice that there is in the group that they did everything to play.”
The Uruguayan warned that Barca were still hungry for more success.
“After a competition like this the majority of teams have a dip,” he said. “But we have to avoid that and we have the desire to keep winning titles and be the best team in the world.”