Madrid, who rested Cristiano Ronaldo, Gareth Bale and Karim Benzema, took the lead with an own goal by ex-West Brom defender Gianni Zuiverloon.

Marco Asensio and Alvaro Morata scored twice each, making them Real's joint top scorers this season with five.

Nacho scored a stunning flying volley to make it 6-0, with Benja puling one back before Mariano's late strike.

The second leg at the Bernabeu is on Wednesday, 30 November.

Real played their first leg a month before everyone else because of their involvement in the Fifa World Club Cup in December, as did Barcelona last season.