UEFA will await reports from the referee and match delegates before deciding whether to investigate the throwing of objects by Villarreal supporters towards Arsenal captain Cesc Fabregas during Tuesday's Champions League quarter-final first leg at El Madrigal.
Fabregas, jeered throughout by the home fans, was taking a corner in the second half, shortly after a clash with Sebastian Eguren, when what appeared to be paper boxes were hurled in his direction from the stands.
Although the Spain international did not seem to be struck directly, he removed one of the objects from the pitch, showing it to Norwegian referee Tom Henning Ovrebo before then taking the corner.
Arsenal manager Arsene Wenger said: "I saw that there were coins or boxes thrown at him. Certainly UEFA will make an inquiry and make the right decisions."
The Gunners battled back to secure a 1-1 draw with a fine overhead kick from Togo striker Emmanuel Adebayor, who had been set up by Fabregas' on 66 minutes.