MADRID, Sept. 8 (Xinhua) -- Athletic Club faces an anxious wait over the groin injury suffered by winger Nico Williams during Spain's 6-0 victory over Turkey in Sunday's FIFA World Cup qualifier.

The 23-year-old was forced off just before halftime, limping from the pitch while clutching the left side of his groin.

"It is a shame," Spain coach Luis de la Fuente said afterward, noting Williams felt "a slight pain in his abductor and he will need to have a test, but it looks like a muscle problem."

Should the injury be confirmed, it would deal a major blow to Athletic ahead of a demanding schedule. The Basque side resumes La Liga action next Saturday with a derby against Alaves, followed by its Champions League opener at home to Arsenal, kicking off a stretch of seven matches in 22 days.

Williams turned down FC Barcelona's advances for a second consecutive summer to commit his future to Athletic, the club where he has spent his entire career. His strong early-season form has helped Athletic match Real Madrid as the only teams to begin the campaign with three straight wins.

The setback is particularly concerning given Williams ended last season sidelined with a pelvic injury that forced him to miss several key fixtures. ■