The Ballon d'Or winner was dismissed after getting involved in an altercation with Athletic's Iturraspe
The Portugal international got involved in a scuffle with Carlos Gurpegui and Ander Iturraspe in the 76th minute of Sunday evening's encounter and was consequently dismissed by referee Miguel Ayza.
Ronaldo had previously set up Jese for the opener in the 65th minute, with Ibai Gomez leveling the scoring shortly before the Ballon d'Or winner's dismissal.
The 28-year-old had last been red carded in Madrid's Copa del Rey final loss against Atletico Madrid in 2013.
Sunday's dismissal was the eighth of his career, having been sent off four times for Madrid and four times during his time at Manchester United.