BARCELONA, Spain (AFP) - Yaya Toure picked the perfect time to get his first Champions League goal for Barcelona, his 43rd minute strike giving the 2006 winners a 1-0 win over Schalke 04 here Wednesday.

After winning their Champions League quarter-final first leg in Germany by the same score last week, Barcelona progressed to a mouth-watering semi-final meeting with English giants Manchester United with a 2-0 aggregate victory.

Toure got the only goal of an entertaining if error-strewn game two minutes before half time, side-footing a loose ball home from the edge of the six yard box.

The Ivory Coast international was the man who found the net but the credit for creating it has to go to their 17-year-old striker Bojan Krkic, Barca's scorer in the first leg, who broke away clear down the right wing.

Barca's teenage prodigy out-sprinted his markers before providing a tricky cross which two Schalke defenders failed to clear properly and Toure was on hand to break his duck for the Catalan club.

There was joy for Barca after their recent dismal displays in La Liga, with only one win in their last seven outings, but both they and Schalke will be regretting their otherwise comprehensive failure to find the net.

"We were not always on the target but at least we played better than in some of our other games," admitted Barca's Spanish international midfielder Xavi Hernandez.

The first half before Toure's goal saw thrilling end-to-end action in which only poor finishing was to blame for neither side scoring.

A host of Barca players failed to capitalise on their opportunities while Schalke target man Kevin Kuranyi squandered no less than four good chances in the first 20 minutes. The second half followed in similar fashion.

Samuel Eto'o and Thierry henry mis-hit almost every ball that came their way while Halil Altintop and Kuranyi were equally inept for Schalke 04.

By contrast to Barca's better-known names, Bojan was a constant threat to Schalke with his darting runs and dribbling. Deservedly, his name rang around the Nou Camp when Barca coach Frank Rijkaard substituted the exhausted teenager after 73 minutes.

One disappointing note for Rijkaard was that his captain Carles Puyol was among the four men booked and the Spanish international will miss the semi-final first leg in two weeks time.

With a long list of injuries, Rijkaard will be hoping that Gabi Milito will have recovered from his groin problem in time for the visit by United.

Nevertheless the victory will ease the pressure a little on Rijkaard and Barca's under-fire president Joan Laporta.

"I don't think too many people can complain if we are in the Champions League semi-finals," commented Laporta after the game.

Barca now face Manchester United in the Champions League semi-finals with the first leg being in the Nou Camp on April 23.

The English Premiership champions beat Roma 1-0 on Wednesday to go through 3-0 on aggregate. This season's Champions League final will be in Moscow on May 21.