Gourriel had a solid season during the 2004–05 Cuban National Series, leading the league in hits and runs. However, he truly dominated in 2005–06, leading the series in RBIs, runs and triples. His 27 home runs, which also led the league, were one short of the record of 28. Gourriel's batting average was .327 and his slugging percentage was .676.
On July 28, 2006, ESPN.com reported that Gourriel and another Cuban national player, Eduardo Paret, had defected from Cuba and into Colombia. Gourriel refuted this claim on August 1, 2006, stating that he returned to his home in Cuba immediately after the conclusion of the tournament the Cuban national team had been playing in.