AZ Alkmaar supporters were eager to disrupt West Ham's preparations for the Europa Conference League semi-final by setting off fireworks outside the hotel.
However, footage of the pyrotechnics in Holland has shown one fan hit by a rocket during the colourful and noisy display.
Darkly-dressed fans were seen running around and stumbling while a bright display of fireworks went off in the night sky above the hotel where West Ham arrived earlier in the day.
The Hammers also took part in a training session at the AFAS Stadion in Alkmaar, which holds 19,478 fans.