Teenage prodigy Takefusa Kubo made his first appearance for Villarreal on Sunday, playing the second half of a 3-1 friendly win against second-division Cartagena.
The 19-year-old Japan midfielder is preparing for his second season in the Spanish top flight after joining Villarreal earlier this month on a one-year loan from Real Madrid.
With Villarreal's new manager Unai Emery making wholesale changes at halftime, Kubo, wearing the No. 16 shirt, slotted into the lineup as an attacking midfielder alongside veterans such as midfielder Vicente Iborra and forward Paco Alcacer.
Villarreal will play further friendlies on Tuesday and Friday in preparation for the new season, which kicks off Sept. 12.
Kubo completed his maiden La Liga campaign last month on loan to Mallorca, which was relegated to the second division following a 19th-place finish.
A former star pupil of Barcelona's youth academy, Kubo transferred to the Catalan giants' archrivals Real from J. League first-division side FC Tokyo last year.