Tottenham striker Vincent Janssen 'lost 20 minutes of his memory' following a collision with Simon Mignolet in Belgium's 1-1 draw with the Netherlands.

Mignolet followed through on Janssen after punching an aerial ball clear in the first period of Tuesday's friendly and the Spurs star was forced from the field with concussion as a result.

An apparently dazed Janssen was replaced by Bas Dost before Davy Klaassen put the Netherlands in front from the penalty spot just before the interval.

Belgium restored parity in the second period as the spoils were shared at the Amsterdam Arena, but Janssen remains a major doubt for the Netherlands' World Cup qualifier against Luxembourg on Sunday.

"Vincent Janssen is going to be a very difficult story," boss Danny Blind told reporters. "The physician told me it is a concussion. He lost 20 minutes of his memory, and doesn't know what happened.

"We have to be careful with that and talk it through."

Tottenham are not in action until November 19 when they face West Ham at White Hart Lane.