Guillermo Gabriel was a member of the Spanish national team in the first European Championship, in 1954. In the championship game, he started at third base for Spain and hit 7th. He went 0 for 4 and was hit by a Giulio Glorioso pitch in a loss to Italy while making one error in six chances at the hot corner. He started at 2B for Spain when they won the 1955 European Championship, their only European title (through 2018). He was also with Spain for the 1957 European Championship.