Real Madrid stumble against Villarreal to allow Barcelona back into title race
Cristiano Ronaldo's excellent 62nd-minute opener had put a below-par Madrid in front, but Senna equalised with a 25-yard free-kick in the 83rd minute.
The real drama came in the aftermath, though, as Mourinho was ordered from the touchline for his reaction to the equalising goal.
Ramos was shown a second yellow in the 85th minute for an aggressive challenge on Nilmar and Ozil was given a straight red moments later, apparently for dissent.
The draw left Madrid just six points clear of Barcelona at the top of the Primera Division.