Ex-Arsenal striker Carlos Vela scored a hat-trick as David Moyes secured his first win as Real Sociedad manager.
Vela, who struggled to make an impact in England, inspired La Real against Elche in former Manchester United boss Moyes's first home game in charge.
The Mexican headed in from close range after three minutes, then struck either side of the break with low drives.
Moyes has four points from two games after a goalless draw against Deportivo La Coruna in his first match.
After having to wait more than two weeks for his first home game with the San Sebastian club, Moyes's debut in front of his new team's supporters could not have gone better.
Despite lots of empty seats at Sociedad's Anoeta Stadium, the hosts began brightly and were ahead when Vela turned in a right-wing cross with a powerful header inside 180 seconds.
It was the kind of potent attacking play which helped them beat Atletico Madrid in their previous home match, and also the type of display which produced their only other league win of the season - a victory over Real Madrid.
But Sociedad have struggled against less high-profile opponents, with only one win from their previous 10 matches.
Elche, though, were obliging opponents and never looked like forcing their way back into the match.
Vela doubled his tally for the night and the season on the half-hour mark when he raced through and slotted a low shot past Elche keeper Przemysław Tyton.
And he completed his hat-trick with a clever toe-poked effort from 12 yards shortly after half-time.
The victory moves Sociedad up from 16th to 12th in La Liga, while Elche remain 19th.
Real Oviedo 0-0 Real Sociedad: David Moyes' Copa del Rey debut is a stalemate
Copa del Rey match was David Moyes' first taste as Real Sociedad boss Clean sheet was Sociedad's third-successive since Moyes took over Return leg takes place on December 17 in San Sebastian Oviedo coach Sergio Egea was sent off after they were denied a penalty
David Moyes’ Real Sociedad made it three games without conceding but could only draw the first leg of their last-16 Spanish Cup tie against third tier Oviedo.
A third clean sheet will please Moyes but his side will now have to finish the job when they meet again in San Sebastian in two weeks, time just three days after the Basque derby against Athletic Bilbao.
Moyes had no luck in the cup at Old Trafford with Manchester United knocked out in the third round against Swansea last season and he watched his side contest a hard-fought goal-less draw at the Carlos Tartiere stadium.
Real Oviedo demanded a penalty when Franck Omgba (left) tumbled over Real Sociedad's Alex Callens tackle
The Copa del Rey clash was David Moyes' first since he became Real Sociedad boss in November
Subs not used: Zubikarai, Estrada, Iker Hernandez, Descarte, Aritz Elustondo.
Booked: Pardo, Ansotegi
He rested five first team players ahead of this weekend’s visit to Villarreal and a second string side fail to penetrate the second division B team’s defence.
Real Sociedad had a penalty shout in the first half when Diego Johannesson looked to have brought down Pablo Hervias inside the area on the half hour but the referee waved away the young winger’s appeals. Hervias was a constant threat for Moyes’ team as Real Sociedad tried to break the deadlock.
Midfielder Ruben Pardo, starting the game in place of the rested Markel Bergara and Esteban Granero, also had a deflected shot go just wide before the break but Oviedo defended well and deserved to go in at half-time on level terms.
David Zurutuza had the first chance of the second half but the Real Sociedad midfielder headed straight at Oviedo keeper Esteban Suarez after connecting with Chory Castro’s free-kick.
Sociedad goalkeeper Geronimo Rulli (right) had to be quick to stop Borja Valle in the second half
Zurutuza went close again with a shot from distance as Real Sociedad pushed for the away goal. They were playing without top scorer Carlos Vela whose hat-trick helped Moyes to his first win at the club last Friday.
Leading the line in place of the rested Mexican and the injured Imanol Agirretxe was the Iceland international Alfred Finnbogason and his best chance came on the hour when Castro crossed from the left but from six yards out he failed to beat Esteban.
Ion Ansotegi (left) hugs Oviedo goalkeeper Esteban after the pair are involved in an incident late in the match
Ansotegi (left) was promptly booked by the referee after his involvement with Esteban
The Oviedo keeper was in fine form blocking a Castro shot moments later. But the home side were also forcing chances and Josep Sené volleyed over from six yards out.
The chance seem to invigorate the minnows and when Franck Omgba tumbled over Alex Callens’ outstretched leg there were calls for a penalty from Oviedo’s players. The referee waved away the appeals and sent coach Sergio Egea off for protesting.
The teams take the 0-0 first-leg scoreline into the return game in San Sebastian in two week’s time. The match comes just after three days after the Basque derby with Athletic Bilbao. Moyes may be tempted to play a more first-choice side to ensure progression in the Spanish Cup.
David Moyes's honeymoon period at Real Sociedad came to an abrupt end with a 4-0 defeat to Villarreal on Sunday – and the manager admitted it could have been far worse.
Moyes, who was sacked by Manchester United in April after just 10 months in charge, had made a promising start at Sociedad, taking four league points and conceding no goals in his first two games.
But that record was shattered spectacularly on Sunday as Villarreal scored four times in the final 27 minutes through Moi Gómez – who hit two - Bruno Soriano and Denis Cheryshev.
Moyes had few complaints about the result. "It could have been more, we could have lost more goals,” he said. “We made some terrible mistakes, defensively bad mistakes, especially with the third and fourth goals.
"In the first 20 minutes of the game we had some opportunities, but not enough tonight. We knew we were coming to a difficult ground and we wanted to be hard to beat, and for 50-60 minutes we were, but in the end (it was) not good enough."
Moyes, whose side have slipped to 14th in the Primera Division, stopped short of criticising his players’ attitude, but said they need to do much better with the ball.
On his midfielders, Moyes said: "I think the players have worked very hard, their effort has been fantastic. The biggest disappointment is that they haven't passed the ball better.
"We need to compete better than we're doing, but their effort has been fantastic, but we're giving the ball away too much."