Barcelona breezed into the Copa del Rey last-16 as a Sandro hat-trick helped them to a 6-1 second-leg win over Villanovense while Mat Ryan's Valencia edged out third-tier opposition in their first leg.
Holders Barca were held to a shock goalless draw in October's first leg and Luis Enrique named Luis Suarez, Neymar and Andres Iniesta on the bench in case of another dogged display from the visitors.
A thunderbolt from Dani Alves with just four minutes played allayed concerns over an upset, however, before Sandro capitalised on a dreadful Villanovense error to make it 2-0.
Juanfran scored a fine strike on a rare Villanovense break to halve the deficit after 29 minutes, but Sandro's second two minutes later killed any hopes of a comeback before half-time, before Munir El Haddadi's header early in the second half made it 4-1.
Sandro clinched his hat-trick in emphatic style midway through the second half and set up Munir for the sixth with a brilliant backheel away from goalkeeper Jose Fuentes, leaving Camp Nou delighted with the efforts of Barca's younger stars.
Barca wasted little time in taking control of the game, with Alves striding forward before blasting a shot from 30 yards out that swerved in the air before rippling the back of the net, despite Fuentes getting a hand to the ball.
Sandro was then gifted his first of the evening after 21 minutes when Fuentes passed the ball straight to the feet of the 20-year-old inside the box, and he took a touch before curling a fine finish into the far top corner.
Barca were given a shock on the half-hour mark when Juanfran collected a loose ball 25 yards out before rasping a shot into the far corner of Jordi Masip's goal, but hopes of a comeback were promptly extinguished.
Aitor Cantalapiedra, who made his debut in the first leg, slid a fine throughball to Sandro, who drilled low beneath Fuentes from 12 yards after bursting into the box.
Barca grabbed their fourth just six minutes after the break, Jeremy Mathieu planting a cross from the left onto the head of the onrushing Munir, who nodded in low at the near post.
Juanfran headed over the bar after a looping Pablo Moraga cross as the visitors tried to breathe life into the contest, but Sandro promptly secured his hat-trick with 21 minutes to play after another fine Barca attack.
Adriano and Sergi Samper combined down the right and the latter's drilled cross was cleared only as far as Sandro, who took a touch before drilling high into the net past Fuentes from close range.
Sandro turned provider on 76 minutes as he raced in behind a static back four before backheeling the ball superbly away from Fuentes, allowed Munir to slot confidently into the far corner from the right of the box, and the home side cruised through the closing stages to seal their place in the next round.
Gary Neville was given an early glimpse of the size of the task facing him at Valencia after his new side - with Australia No.1 Ryan in goal - were forced to come from behind to beat Barakaldo.
Despite being appointed on Wednesday, Neville will not take charge of the team until the weekend, leaving brother Phil to assist caretaker-boss Voro in the last 32, first-leg fixture.
Alain Arroyo stunned the visitors by netting the opener after 16 minutes but Valencia avoided embarrassment as goals from Joao Cancelo, Jose Gaya and a Dani Parejo penalty secured a 3-1 win.
Deportivo La Coruna were forced to come from behind to earn a 2-1 win away to Segunda Division strugglers Llagostera.
Juanjo Exposito gave the hosts a surprise 22nd-minute lead before Federico Cartabia equalised on the hour mark.
Despite the subsequent sending-off of Luisinho for a second bookable offence, Deportivo grabbed victory through Oriol Riera 14 minutes from time.
Goals from Coke, Michael Krohn-Dehli and Ciro Immobile gave Sevilla a 3-0 win away to UD Logrones, while two for Iago Aspas and a third from John Guidetti saw Celta VIgo win 3-1 in Almeria.
In two all-Primera Division ties, Sporting Gijon slumped to their fourth straight defeat as goals from Alvaro Vadillo and Juan Vargas gave Real Betis a 2-0 first-leg win in Seville, while Rayo Vallecano beat Getafe by the same score.