Bayern Munich took a significant step towards the semi-finals of the Champions League with a commanding 2-0 first-leg success over a strangely subdued Juventus side at the Allianz Arena on Tuesday evening.After opening the scoring inside a minute courtesy of a deflected drive from David Alaba, the runaway Bundesliga leaders dominated what many felt would be the most closely contested of the four quarter-finals and were full value for a victory which was deservedly capped by a second-half strike from Thomas Muller.Bayern had gone into the game on the back of a devastating 9-2 domestic defeat of Hamburg but even they could not have imagined that they would open the scoring against the tightest defence in the Champions League with such ease.Less than 25 seconds had elapsed when an uncharacteristically sloppy pass from Andrea Pirlo allowed Bastian Schweinsteiger to put Alaba into space some 35 yards out. Even then, there appeared to be little threat to the Juventus goal, but the Austria international’s subsequent strike took a slight deflection off Vidal that deceived Gianluigi Buffon, who, having inexplicably committed himself to a dive to his right, was unable to scramble back across his line to keep out a bouncing ball that was not travelling at any great pace.Credit to the visitors, they responded well to the concession of such an early goal, and Pirlo fired a free kick just over the Bayern bar seconds before midfield partner Vidal flashed a well-struck shot inches wide as the Bianconeri enjoyed a brief spell of dominance.The loss of Toni Kroos to injury after 16 minutes appeared further cause for concern for Bayern but the introduction of Arjen Robben coincided with a sustained spell of pressure for the hosts, with the Dutchman very nearly doubling his side’s advantage with a snapshot volley that Buffon did well to block with his feet.Franck Ribery then saw a low strike unluckily deflected wide by Bonucci, after the industrious Mario Mandzukic had brilliantly dispossessed a sleeping Andrea Barzagli, before Robben squandered another excellent opening on 32 minutes, dragging Muller's terrific cut-back wide of the right post with the entire goal at his mercy.Juve served a timely reminder of their set-piece threat just before the break when Giorgio Chiellini headed a Pirlo corner just over, but it was clear that the Bianconeri, who had not managed a single shot on target in the opening 45 minutes, would need a drastically improved second-half showing if they were to save an unbeaten away record in European competition that stretched back to 2010.As it was, Bayern continued to carry the far greater attacking threat and Mandzukic tested Buffon with a low strike after being released into space by Schweinsteiger. The crucial second goal that Bayern undeniably deserved arrived just after the hour mark.Again, there was some fortune involved. Mandzukic was offside when Luiz Gustavo hit a shot that Buffon was unable to hold, but the hosts deserved their good luck and Mandzukic had to be applauded for the way in which he coolly collected the rebound before leaving Muller with a tap-in.The beleaguered Bianconeri managed to muster a shot on goal in the final quarter, with Manuel Neuer easily parrying a Vidal shot away to safety, but Muller very nearly added a third Bayern goal at the end of what was already a bitterly disappointing night for the Italians. They must now attempt to overturn a two-goal deficit in the second leg without Vidal and Stephan Lichsteiner, both of whom where booked in Bavaria.