Viktor Gyokeres required treatment for nearly four minutes after sustaining a cut to his head during Arsenal's opening Champions League match with Athletic Club.
The Arsenal forward clashed heads with his team-mate Gabriel Magalhaes as the pair attempted to attack a free kick into the Athletic Club box.
Gyokeres and Gabriel both fell to the turf following the incident in the 30th minute of the match at the San Mames Stadium, with the former coming off worse in the collision.
Medical staff were required to attend to Gyokeres, with footage showing that the forward had sustained a gash to the back of his head.
The Swedish forward was seen bleeding as he received treatment for the wound.
Gyokeres was eventually patched up by Arsenal's medical staff, with the £64million summer signing sporting a black headband as he returned to the action.
Viktor Gyokeres suffered a gash to the back of his head following a clash with Gabriel
Gyokeres was seen bleeding after the clash as both Arsenal stars attacked a free kick
Gyokeres was able to continue with the Arsenal forward sporting a black headband
The match was able to resume following a four minute delay to proceedings.
The incident occurred with the match goalless at the San Mames, as Athletic Club looked to frustrated one of the tournament favourites.
Gyokeres attempted to continue his impressive start to life at Arsenal, where he has scored three goals in his opening four appearances.
The forward had four shots before eventually being substituted in the 65th minute of the match.
Gyokeres was replaced by Leandro Trossard as Arsenal continued to push for a breakthrough.