Slovan Bratislava defender Kenan Bajric was taken to hospital after being knocked out by Wolves striker Raul Jimenez in their Europa League clash at Molineux.
The Mexican striker was attempting an overhead kick in the 78th minute with the game at 0-0 when he struck the opposing player clean in the face.
Bajric was instantly knocked unconscious and collapsed to the turf, sparking frantic concern amongst team-mates and Jimenez as he hit the deck.
He was placed into the recovery position as Bratislava’s goalkeeper took swift action to prevent him from swallowing his tongue before medics from both sides rushed onto the field.
They took plenty of care with the defender as he was carefully placed onto a stretcher after receiving treatment for several minutes.
Jimenez later headed in the winner but was quick to send his best wishes to his opposition after the game.
“It is difficult for all of us,” Jimenez said. “I don’t know what to say. I hope he recovers well.
“It is a very important win for us and our aspirations. It is all about my team-mates. We all did very well and here we are with three points and almost in the next round.”
Molineux rose in warm applause as Bajric was stretchered off and replaced ahead of the closing stages of the game whilst Jimenez was given a yellow card.
And Slovan Bratislava coach Jan Kozak confirmed the player would be staying in Wolverhampton for further observation as his team-mates travelled home.
Kozak said: “At the moment it looks quite serious. He’s not going home with us. He will be staying here in hospital for observation.
“It’s a head injury – concussion, but he’s conscious. We don’t have any more information but he will stay in Wolverhampton in hospital.”
The game was level at the time of the incident with Wolves looking for a breakthrough, with Jimenez looking to get on the end of an Adama Traore cross.
The result of the injury was 12 minutes of added time after the time for which Bajric was being treated.
And in added time, Jimenez rose with his head rather than his boot to meet a Traore cross and snatch a crucial win for his side.
Ruben Neves missed a penalty for Wolves early in the second half.
But the three points saw them move onto nine points, one behind Braga at the top of the group and five points clear of Bratislava in third place in Group K.
They are now on course to reach the last 32 and have won three consecutive European games for the first time since their route to the UEFA Cup final in 1971/72.