Mina latched on to a classy through ball from former Barcelona midfielder Denis Suarez and produced a clinical low finish to equalise in the 85th minute.
Celta took an early lead through Russian striker Fedor Smolov but Real responded through Toni Kroos in the 52nd minute before captain Sergio Ramos put Zidane's side in front in the 65th from the penalty spot.
The draw ended a five-game winning streak in the league for the leaders and left them on 53 points after 24 games, one ahead of second-placed Barcelona who beat Getafe 2-1 at home on Saturday.
Celta meanwhile climbed out of the relegation zone into 17th place in the standings. (Reporting by Richard Martin Editing by Ian Chadband)