Vazquez provided the cross for Karim Benzema’s opener in an eventual 2-1 win but had to go off on the cusp of half-time and replaced by Alvaro Odriozola following a collision with Sergio Busquets.
Vazquez’s versatility has been of huge importance for Real Madrid this season as he has had to fill in at right back for the injured Dani Carvajal.
The 29-year-old Spain international is out of contract at the end of the season and it remains to be seen whether he will be offered a new contract to remain in the Spanish capital, with Chelsea and Manchester United reportedly interested in taking up his services.
A statement posted on the club's website read: "Following tests carried out today on Lucas Vazquez by the Real Madrid Medical Services, he has been diagnosed with a sprain to the posterior cruciate ligament in his left knee.
"His recovery will continue to be assessed."
Vazquez remains upbeat about the situation though as he posted on Instagram:"I’m going to have to help the team from the sidelines for a while. Gutted, but never down. If there’s one thing this club has taught me it’s to always fight. From this moment I’m giving all I can to be back as soon as possible and help this team in the final stages. Thanks to everyone for your messages and support.
"One objective - keep fighting for La Liga and the UEFA Champions League!"
The former Espanyol loanee has made 34 appearances in all competitions for Real Madrid this season, scoring two goals.
