Gavi marked becoming Spain's youngest player at a major tournament with a goal in an emphatic 7-0 win over Costa Rica as La Roja kicked off their Qatar 2022 campaign in style.
Group E rivals Germany suffered a shock 2-1 loss to Japan earlier on Wednesday, but Spain did not look under any threat after Dani Olmo gave them an 11th-minute lead.
That was La Roja's 100th World Cup goal and another two followed inside the opening 31 minutes through Marco Asensio's strike and a Ferran Torres penalty.
Torres doubled his tally early in the second half and Gavi then steered in a delightful volley, before substitutes Carlos Soler and Alvaro Morata added two more late on.