By Mark Elkington

MADRID (Reuters) - Champions Real Madrid started the defense of their La Liga title with a frustrating 1-1 draw at home to Valencia on Sunday, despite dominating the match at the Bernabeu.

Gonzalo Higuain gave them a 10th minute lead from Angel Di Maria's cross and, in stifling temperatures, Jose Mourinho's side comfortably held the visitors at bay until just before the break.

Valencia showed few ideas going forward but leveled when Jonas headed in from a free kick.

Goalkeeper Diego Alves was the visitors' outstanding player in the second half, keeping out a string of efforts as Real pressed, to help earn a point for their new coach Mauricio Pellegrino.

Real's arch-rivals Barcelona were playing at home to Real Sociedad later on Sunday.

Up on the north coast, Real Betis overcame Athletic Bilbao at San Mames in an eight-goal thriller.

The visitors were three goals up in 31 minutes before last season's Europa League and King's Cup finalists responded in the second half.

Bilbao's Oscar De Marcos got a goal back just after the break and Mikel San Jose then struck twice to level the scores with 14 minutes to go before Betis finally triumphed late on through Alejandro Pozuelo and Jorge Molina with his second.

(Editing by Matt Barker)