Ronaldo scored twice in three minutes to salvage a point for Real and deny Las Palmas a first ever win at the Bernabeu, converting a penalty and heading home from a corner one minute from time.
Isco had given Real the lead in the eighth minute but the goal was swiftly cancelled out by Las Palmas midfielder Tana.
A Jonathan Viera penalty put the visitors ahead in the 56th minute after Bale had been dismissed for two bookings and Kevin Prince-Boateng stretched Las Palmas' lead, but Real, who had three goals ruled out, refused to give in.
Real are second in the standings on 56 points, one behind Barcelona who thrashed Sporting Gijon 6-1 on Wednesday, but Zinedine Zidane's side have a game in hand on their arch-rivals as they seek a first league title since 2012.
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(Reporting by Richard Martin, editing by Ed Osmond)
