Kick-off was delayed by 35 minutes after police attempted to hold back people attempting to force their way in and Liverpool have demanded an investigation into the “unacceptable issues” faced by their fans.
Television footage showed images of young men, who did not appear to be wearing the red Liverpool jerseys, jumping the gates of the stadium and running away. Other people outside, including children, were tear-gassed by riot police, a Reuters witness said.
Some riot police officers stormed into the stadium while others charged at people trying to knock down stadium gates.
European soccer’s governing body UEFA blamed fake tickets for causing the issue and said it would review the events together.
Courtois, who produced a number of fine saves as Madrid won 1-0, tweeted on Sunday morning: “I feel sorry for @LFC fans and the way they were treated. I hope everyone got home safe!”
Additional reporting from Reuters