The former Feyenoord midfielder jumped over a tackle before collapsing and grabbing his knee. Milambo was heard screaming in agony after the non-contact injury, which indicates a possible knee ligament injury.
Seven-time Netherlands U21 international Milambo was stretchered off shortly before half-time and replaced by FC Groningen midfielder Jorg Schreuders.
Milambo wasn't the only Oranje player to get forced off with an injury - Como winger Jayden Addai sustained a hamstring injury in the 20th minute and was replaced by AZ talent Ro-Zangelo Daal.
Eased into Premier League
The 20-year-old Milambo joined Premier League outfit Brentford last summer after spending 11 years at Feyenoord, who reportedly got €20 million for the youth academy product.
Milambo was a starter in the early stages of Brentford's season, but was quickly demoted to a spot on the bench and has played just 68 minutes across all competitions since the start of September.