Goals from Arsenal players new and old gave La Roja a comfortable 2-0 lead at half-time, Santi Cazorla driving the ball home from 25 yards before Cesc Fabregas converted Jesus Navas' cross with a sublime volley. However, the European champions appeared to ease off the gas after the interval, allowing Marc Cintron to half the deficit in the 65th minute.
Spain held on to secure a nervy 2-1 victory, prompting the Seleccion manager to tell Marca: "It was just a pre-season game and it wasn't really a great game. Puerto Rico played to their strengths, as we predicted they would, playing very defensively then suddenly pulling off a surprise counter-attack to score their only goal.
"It was, however, a display of Spanish superiority. The players rose to the occasion and responded well to the challenge that we knew we would face. That was the first step of our preparation for the World Cup in Brazil in 2014, the next step is the qualifier against Georgia."
Spain's margin of victory might have been greater, though, if not for both their hosts' well-drilled defence and a stunning individual performance from goalkeeper Bill Gaudette. Gerard Pique crashed a shot against the post early on, with Gaudette repelling both a Fernando Torres header and a Cazorla rocket.
Speaking to AS, Del Bosque added: "We're not making excuses. At no time did we underestimate the opponent because we never underestimate anyone. We know our world and European titles afford us some prestige but we played with passion.
"We played the whole game in their half, they didn't cause us any problems in defence apart from when they scored their goal. We just lacked a little finesse and good fortune and hit the post twice."