French striker Karim Benzema scored three goals for Real Madrid to silence host Chelsea at Stamford Bridge.
The visiting La Liga club found the net twice before Kai Havertz pulled one back for the title holders in a UEFA Champions League quarter final tie on Wednesday night.
Mendy’s schoolboy error, however, helped Benzema extend Madrid’s lead to 3-1.
To stand any chance of proceeding to the next stage of the competition, Chelsea will have to win by at least two goals in the reverse fixture away to Madrid.
La Liga club Villarreal also defeated German giants Bayern Munich 1-0 tonight.
Bayern can still go through to the second round if they beat the Spanish club in the reverse fixture.
