David Moyes maintains unbeaten start at Real Sociedad

Moyes took over as coach of the Basque club last month and has presided over a draw and a win in La Liga, as well as the stalemate in Oviedo which gave Sociedad a slight advantage ahead of the return in San Sebastian in two weeks.

"We knew we were playing at a very tough stadium against a team who are fighting for promotion to the second division," Sociedad midfielder Ruben Pardo told Spanish television.

"It's going to be a very nice match at the Anoeta and we are really looking forward to playing it," he added.

Villarreal have one foot in the last 16 after they held on with nine men for a 2-1 success at third-tier Cadiz.

Defender Adrian Marin was shown a straight red card in the 59th minute and Israel Puerto was forced off due to injury when Villarreal had already used up their three substitutions.

Valencia, the 2008 winners, gained the upper hand over Rayo Vallecano in their first leg when they fought back from a goal down to beat their La Liga rivals 2-1 in Madrid.

Holders Real Madrid and 2010 winners Sevilla are through to the last 16 after completing crushing aggregate wins against third-tier Cornella and second-division Sabadell respectively.

Both ties were brought forward because of Real's participation in the Club World Cup and the resulting disruption to the La Liga calendar caused by this month's tournament in Morocco.

Real are almost certain to meet Atletico Madrid after the La Liga champions, who beat their city rivals 2-1 after extra time in the 2013 Cup final, won their last-32, first leg 3-0 at third-tier Hospitalet on Wednesday.

The winners of a probable tie between Real and Atletico are likely to meet record winners Barcelona in the quarter-finals.

A second-string Barca side, missing most of their regular starters including Lionel Messi and Neymar, thumped Huesca, another third-tier club, 4-0 on Wednesday.