Albion were beaten 1-0 in their latest pre-season outing against Balearic opponents RCD Mallorca.
David Lopez's bundled finish was the difference between the sides at the Baggies' training ground HQ.
Albion started brightly and Jed Wallace came closest to breaking the deadlock on 15 minutes. A quick free-kick saw the ball come to the skipper, only for his goal-bound effort to be blocked.
The visitors did threaten themselves, though, with Alex Palmer smartly saving after a cross from the right was diverted goalwards just after the half-hour.
Further opportunities came the hosts' way in the second half, as Wallace, Ousmane Diakité and Brandon Thomas-Asante came close to opening the scoring.
But it was the La Liga side who would open the scoring when Lopez followed in to bundle home in the area after Palmer had tipped Antonio Sánchez's free-kick onto the post.
The Baggies pushed for an equaliser as substitutes Fenton Heard, Tom Fellows and Ollie Bostock all threatened to level the game. But despite a late flurry of chances, it ended in a 1-0 defeat.
ALBION XI first 45: Palmer, Furlong, Bartley (Ajayi 45), Heggem (Taylor 45), Townsend (Heggem 70), Mowatt (Heard 70), Molumby (Diakité 45), Wallace (Bostock 70), Swift (Thomas-Asante 45), Grant (Fellows 45), Maja (Swift 70).
Subs not used: Cann, Hall, Whitwell.
