A late goal by Muniain saw Barcelona suffer their first league defeat of the season, losing 1-0 at Athletic Bilbao.
This followed their first defeat of the season against Ajax in the Champions League and means that Atlético Madrid are now level with Barca on points at the top of La Liga with Real Madrid three points adrift in third.
Athletic Bilbao move up to fourth in La Liga, but eight points adrift of Real Madrid.
A hat-trick for Jonas saw Valencia cruise past Osasuna 3-0 on Sunday while Sevilla overcame Granada 1-2 with goals from Bacca and Gameiro. Brahimi scored from the penalty spot for the home side. Ten yellow cards in this encounter.