By Simon Baskett

MADRID, Jan 31 (Reuters) – Barcelona reached the semi-finals of the King's Cup on Thursday after a Thierry Henry header earned them a 1-0 aggregate victory over 10-man Villarreal at the Nou Camp.

The French striker scored the only goal of the tie when he planted a well-placed header beyond the reach of Villarreal keeper Diego Lopez four minutes before halftime.

Earlier Racing Santander, who are riding high in fifth place in the league, made the semi-finals for the first time after a 3-3 draw at Athletic Bilbao put them through 5-3 on aggregate.

The two sides will join last season's losing finalists Getafe and Ronald Koeman's Valencia in the hat for Friday's semi-final draw.

Anxious to appease their fans after falling nine points behind Real Madrid in the league last weekend, Barca made a lively start against Villarreal.

Argentine forward Lionel Messi proved a constant menace to the Villarreal back four with his electric runs from midfield, but despite manufacturing a host of scoring chances Barca were frustrated by some top-class goalkeeping from Lopez.

The Catalans eventually broke the deadlock late when the unmarked Henry headed in after Deco had floated a free kick into the area and moments later Villarreal received another blow when defender Pascal Cygan was sent off after picking up a second booking for a foul on Messi.

CONTROVERSIAL PENALTY

Barca should have extended their lead when they were awarded a controversial penalty 15 minutes from time, but Lopez made a great full-stretch save to stop Messi's spot kick.

A huge cheer went up when Ronaldinho came off the bench to make his first appearance of the year after recovering from a knee injury but there were sighs of relief at the final whistle as Barca withstood a late surge.

In the earlier semi, Racing looked to be in trouble at San Mames after their first leg lead was wiped out in less than half an hour thanks to a glancing header from defender Fernando Amorebieta and a penalty from Inaki Munoz.

But Racing turned the tables early in the second half, Argentine midfielder Aldo Duscher grabbing an all important away goal when he stabbed home at the near post.

Now needing two goals to go through, Bilbao piled forward and Markel Susaeta made it 3-1 almost immediately, but Racing hit back with a close-range shot from striker Mohamed Tchite.

Midfielder Oscar Serrano completed a memorable night for the Cantabrians when he scored his side's third in added time.

(Editing by Justin Palmer)