Tottenham defender Jan Vertonghen had to be carried from the pitch after initially being allowed to carry despite a brutal head knock.
The Belgian collided with Ajax keeper Andre Onana and his own team-mate Toby Alderweireld during during the first-half of the Champions League quarter-final in London, reports The Mirror .
All three were left in a heap on the floor but there was major concern for Vertonghen as blood poured from his nose.
Medical staff rushed on to assist him and, after being cleaned, he briefly left the field.
But the decision was then taken to allow Vertonghen to continue playing.
However, it wasn't long before he pulled up again and had to be assisted down the tunnel in worrying scenes.
Tottenham currently trail the Dutch side 1-0 in their last four encounter but the incident with Vertonghen has overshadowed an excellent game of football.
As the second-half got under way, BT Sport reported that the centre-back was receiving further treatment in the medical room.
Donny Van de Beek gave Ajax the lead after 15 minutes after sneaking in behind the Spurs defence.
He finished coolly beyond keeper Hugo Lloris to give Ajax a foothold in the tie.
Liverpool will meet Barcelona in the other last 4 showdown on Wednesday.
