The Dominican Republic suffered their first World Baseball Classic defeat in eight years on Tuesday after being downed 3-1 by Puerto Rico in their opening second round game in San Diego.
The defending champions, who became the only team in history to go through the tournament unbeaten en route to the 2013 crown, were undone by Puerto Rico's deep bullpen and a superb display by veteran catcher Yadier Molina.
Molina bludgeoned a home run, drove two more runs and captured a baserunner at a key stage late in the game to help bring Puerto Rico home in a tense Pool F opener at Petco Park.
The Puerto Rico win ended an 11-game winning streak in the competition for the Dominican Republic, and left Puerto Rico dreaming of a place in the semi-finals in Los Angeles.
In contrast to their free-scoring performances in the first round, when they averaged more than nine runs per game, Puerto Rico were made to work harder against the champions.
The Dominican Republic meanwhile, who had also racked up the runs in the first round, with 26 in three games, were held to just six hits.
They looked to be clicking into gear when Nelson Cruz belted a leadoff homer in the second inning.
But thereafter Puerto Rico's pitching dominance came to the fore, holding the champions scoreless.
Remarkably, Puerto Rico's bullpen is made up of little-known journeymen plying their trade across the globe, led by Hector Santiago, who plays in China for the Lamigo Monkeys.
The victory leaves Puerto Rico firmly in control of their own destiny in Pool F. Two teams from the group, which also includes the United States and Venezuela, will qualify for next week's semi-finals.
Puerto Rico, who had not beaten the Dominican Republic since 2006, will now face hosts the United States in their second game on Friday.