The striker stabbed home his second goal of the campaign at the end of a second half which the hosts dominated.
It was Betis' second straight 1-0 success after Ruben had left it even later to seal an opening-day win at Granada.
Osasuna claimed their first victory of the season with a 2-1 win over Sporting Gijon thanks to two wonderful first-half goals.
After an eventful opening quarter the hosts went ahead when Nino tapped home on 28 minutes after a great pass from Kike Sola split the Sporting defence wide open.
Then, two minutes later, Osasuna doubled their lead through Alvaro Cejudo's volley from Sergio's cross into the top corner.
The home side should have been further ahead but gave Sporting a lifeline on 75 minutes when Diego Barral's shot went straight through goalkeeper Andres Fernandez, but they held on to claim all three points.
Javi Fuego missed a second-half penalty as Rayo Vallecano were held to a goalless draw by Real Zaragoza in a poor game at Las Vallecas.
Paulo Da Silva's handball gave Rayo the perfect opportunity to make a winning start at home on their return to the Primera Liga but Roberto Jimenez saved Fuego's penalty with 20 minutes remaining.
Zaragoza offered little as an attacking threat and Angel Lafita's tame effort in the first-half was their best effort on goal.
Racing Santander had to settle for their first point of the season after failing to break down a resilient Levante at El Sarindero.
Lautaro Acosta had the best chance for the hosts early in the second-half but blazed over with only goalkeeper Gustavo Munua to beat.
Racing were reduced to 10 men when Papa Kouli Diop was dismissed for a second yellow card on 80 minutes and Levante nearly made the extra man count but Tono Martinez saved Nabil El Zhar's late effort.
Sergio Garcia scored twice as he inspired Espanyol to an impressive home win over Athletic Bilbao.
Garcia headed his side in front after 25 minutes and almost blocked Fernando Llorente's equaliser on the line before scoring a technically brilliant, opportunistic winner 16 minutes from time.
Victory puts defeat in the opening game behind Espanyol, while Bilbao have just one point now from six.
Preview of Monday's Match