Puerto Rico's Giancarlo Alvarado combined with two relievers on the shutout in what was the opening game for both teams in the tournament's Pool C. Puerto Rico and the Dominican Republic are both 1-0 in the round-robin phase of the event while Spain and Venezuela are 0-1.
The top two teams in the pool will advance to the second round.
Angel Pagan opened the Puerto Rico first with an infield single and moved to second on a sacrifice by Irving Falu.
Alvarado pitched four innings, giving up a lone hit with four strikeouts and no walks. Hiram Bugos came on in the fifth and worked into the ninth, allowing four hits. After Bugos issued a two-out walk in the ninth, Xavier Cedeno came on to strike out the final batter.
Both teams will be in action again Saturday with Spain meeting the Dominican Republic and Puerto Rico taking on Venezuela. Both the Dominican Republic and Puerto Rico can clinch spots in the second round with a win Saturday.