Barcelona tore Bayern Munich to shreds at the Nou Camp to all but reach the Champions League semi-finals.Leo Messi scored twice, skipping clear of a shambolic defence to stroke in Samuel Eto'o's pass after nine minutes.The 21-year-old Argentine magician then set up Eto'o to fire home the second and had a strong penalty shout turned down before tapping in Henry's cross.Henry finished another free-flowing move before half-time and Bayern's only consolation was a goalless second half.A 5-1 thumping at the hands of Wolfsburg at the weekend had Bayern fans fearing the worst against an in-form Barca - but they could not have imagined just how badly it would turn out.Defensively, Jurgen Klinsmann's side were awful, as the first goal typified.Christian Lell, standing in at left-back in place of the injured Phillip Lahm, left Messi all on his own to run onto Eto'o's pass and calmly pass the ball into the net.Only three minutes later, Bayern were 2-0 behind when Messi turned provider for Eto'o, who just about stayed onside and finished into the far corner through keeper Hans Jorg Butt's legs.Barca kept up the pressure, slick in possession and tenacious in their efforts to win back the ball on the rare occasions they lost it.They could - and probably should - have had a spot-kick when Messi dinked the ball past Lell and fell under the challenge.But English referee Howard Webb waved away the penalty claims and, to Barca's horror, showed a yellow card to the Argentine for diving.Despite his side's comfortable lead, Pep Guardiola was incandescent - and the Barca boss was sent to the stands by Webb for his protests.The hosts quickly got back to the job in hand.Andres Iniesta carved open the Bayern defence with his pass but Butt anticipated Henry's run and came out to meet the former Arsenal striker, taking an accidental kick in the face in the process.A lengthy spell of treatment for the keeper interrupted Barca's momentum, but they added a third on 38 minutes.Henry, in a move reminiscent of his Arsenal days, produced a burst of pace on the left to leave Massimo Oddo trailing in his wake before squaring for Messi to tap in from close range.There was still time for Henry to get on the scoresheet before the break.Messi cut in from the right and was floored by former Barca midfielder Mark van Bommel's cynical shoulder barge.But Webb played the advantage, Eto'o picking up the loose ball and moving it to the left for Henry to sidefoot low into the far corner.Van Bommel was fortunate to escape a yellow card - or perhaps even a red - but that was a rare bit of good news for the German giants.They did improve after the break, with substitute Andreas Ottel adding some much-needed steel in midfield.Ze Roberto might even have scored a consolation but was denied by a fabulous block by Barca skipper Carles Puyol.However, the home side had more chances of their own on a dream night at the Nou Camp.The irrepressible Messi was denied his hat-trick by an excellent Butt save and, right at the death, saw a shot hit team-mate Seydou Keita on the line.At the final whistle, a tearful Franck Ribery was consoled by France team-mate Henry.Bayern face a near impossible task in the return leg on Tuesday if they are to stop Barca booking a semi-final against Chelsea or Liverpool.Source: BBC