Valencia came from behind twice to defeat Levante 4-2 courtesy on Sunday night at Estadio de Mestalla.
Gabriel and Maximiliano Gomez twice levelled matters in the first stanza before Manu Vallejo scored two late goals to seal a thumping win.
Jose Morales' first-half brace was not enough to avoid defeat for the visitors.
Real Betis had a perfect start to the season after netting deep in stoppage time to sink Deportivo Alaves 1-0 on Sunday afternoon at Estadio Mendizorrotza.
After a goalless first stanza and virtually another half without goals, Cristian Tello finally snatched the winner for Betis deep in stoppage time.
Real Valladolid were denied a winning start after being held to a 1-1 draw by Real Sociedad on Sunday afternoon at Estadio Jose Zorrilla.
Michel broke the deadlock for the hosts five minutes before the break but Roberto Lopez levelled matters for Sociedad on the hour-mark to ensure the share of the spoils.
Villarreal came from behind to salvage a point against newly-promoted side Huesca in a 1-1 draw on Sunday evening at Estadio de la Ceramica.
Pablo Maffeo gave the visitors a shock lead just before the break and Gerard Moreno avoided defeat for the Yellow Submarine by snatching the equaliser in the last 22 minutes from the penalty spot.
Huesca thought they had netted a stoppage time winner after finding the back of the net but the goal was disallowed for offside after a Video Assistant Referee Review.
Osasuna started on a good note after dispatching newly-promoted side Candiz 2-0 on Saturday night at Estadio Ramon de Carranza.
Adrian got the opener for the visitors in the tenth minute and Ruben Garcia wrapped up the three points for Osasuna in the last ten minutes.
Granada had a perfect start after upsetting Athletic Bilbao 2-0 on Saturday evening at Estadio Nuevo Los Carmenes.
After a scoreless first stanza, Yangel Herrera broke the deadlock four minutes from the break and Luis Milla effectively secured the three points for the hosts with the second goal four minutes later.
Ten-man Eibar got away with a point after holding Celta Vigo to a goalless draw in their opener on Saturday afternoon at Estadio Municipal de Ipurua.
The hosts were educed to ten men after Pape Diop g picked up a second yellow card and was dismissed in the last three minutes.