WATCH: Video shows worrying nature of Jan Vertonghen injury against Ajax

Jan Vertonghen didn’t look to be in a good way when leaving the pitch during Tottenham’s Champions League semi-final defeat to Ajax on Tuesday night.

The defender required treatment on a gash to his face after clashing in the air with teammate Toby Alderweireld 10 minutes before half-time.

After leaving the pitch, Vertonghen seemed to get the all-clear and returned to the action.

But the Belgian lasted a matter of seconds before heading back to the sidelines.

He then appeared to suffer from the effects of a delayed concussion. Watch footage of the incident below.

Vertonghen just went from bad to really bad in real time. Looks like a concussion. pic.twitter.com/xkS9SziEsU

— Give N'Golo (@FPLHazardous) April 30, 2019