MADRID, Jan 28 (Reuters) - Second division Alaves reached the semi-finals of the King's Cup with a 4-3 aggregate victory over Celta Vigo, despite losing 1-0 to the Primera Liga strugglers in Wednesday's second leg.

Real Madrid and Sevilla joined Alaves in the last four by completing emphatic aggregate wins over Valencia and Atletico Madrid in the day's other quarter-finals.

Real, leading 3-0 after the first leg at the Bernabeu, won the return 2-1 with goals from Raul and Zinedine Zidane to make it 5-1 overall.

Sevilla put behind them the sale of Spanish international forward Jose Antonio Reyes to Arsenal by booking their place in the semis, completing an emphatic 6-1 aggregate victory over Atletico Madrid with a 2-1 win at the Calderon.

With prospective new coach Radomir Antic watching from the stands, Celta started well enough but spurned several early chances and became frustrated as Alaves closed them down in midfield.

Celta finally managed to get the ball in the net midway through the second half when Alaves keeper Juan Pablo fumbled a Gustavo Lopez free kick, but the visitors won through to the semis with a disciplined defensive display.

HUGE LEADS

There was never any doubt about the outcome of Wednesday's other two ties, with Real Madrid and Sevilla both holding huge leads after the first legs.

Raul ended all hopes of a heroic Valencia comeback when he raced on to a sharp through ball from Ronaldo to guide home on 14 minutes.

Ronaldo could have made the Valencia task even more difficult if he had not missed the target with an angled drive just before halftime.

Valencia created several chances against a Real side missing suspended midfielder David Beckham, but their only reward came when substitute Xisco nodded into an open goal after fellow striker Mista had headed on to the bar 16 minutes from time.

Valencia were denied the slim satisfaction of a draw on the night when Zidane's free kick ricocheted in off the wall and past helpless keeper Andres Palop two minutes into injury-time.

In the remaining quarter-final, Barcelona will be looking to turn the tie around after their disappointing 1-0 home defeat when they travel to Real Zaragoza on Thursday.

By Simon Baskett