The Nigerian, 23, received immediate medical attention after falling to the ground in the sixth minute.

He walked off the pitch minutes later holding an ice pack against his head.

Kalu resumed playing after getting treatment but was substituted after he appeared dazed.

"It gave us a bit of a chill and it's still quite shocking," said Oudin, who replaced him in the 14th minute.

Players from both teams formed a wall around Kalu as he was receiving medical attention.

"According to the doctor, it was just a dizzy spell," he added at full-time, having scored Bordeaux's equaliser as they fought back from two goals down to earn a draw.

"We're happy for Kalu, everything is fine and that's the most important thing," Oudin said.

"We inevitably thought about what happened with (Denmark midfielder Christian) Eriksen, the whole team and everyone was scared."