- The visitors' seven-game unbeaten streak in La Liga was ended.
MADRID: Youssef En-Nesyri's fantastic first-half strike helped Sevilla seal a 1-0 derby victory over Real Betis on Sunday to take a big step towards securing a top-four spot in La Liga.
The Moroccan backed up his midweek Champions League double in Sevilla's last-16 exit at the hands of Borussia Dortmund with a 27th-minute winner.
Julen Lopetegui's men bounced back from successive league defeats to move six points clear of fifth-placed Real Sociedad, who lost 1-0 at Granada, in the race for the Champions League.
They sit 12 points behind leaders Atletico Madrid, with a game in hand.
Betis, on a four-match winning run and only six points behind their city rivals before kick-off, proved tough opponents at the Ramon Sanchez Pizjuan.
The key moment came when Jesus Navas' long ball over the top was brilliantly brought down by En-Nesyri, who then rounded goalkeeper Joel Robles and slotted in from a tight angle, on the run. The 23-year-old has now scored 20 goals this season in all competitions.
Betis fought hard but struggled to create any clear-cut chances and their hopes of forcing their way into the top four now appear remote.
Earlier on Sunday, Real Sociedad's hopes of qualifying for the Champions League suffered a blow with a defeat at Granada.
The visitors' seven-game unbeaten streak in La Liga was ended.
Granada moved up to eighth thanks to defender German Sanchez's 52nd-minute goal.
Atletico Madrid lead city rivals Real Madrid by six points at the top of the table after their goalless draw at Getafe on Saturday, when Real beat Elche.
Third-placed Barcelona could move within four points of Atletico when they host bottom side Huesca on Monday.