MADRID : Barcelona's Robert Lewandowski scored a quick-fire second-half double to set the leaders on course for a 4-0 thrashing of Real Madrid in a stunning Clasico victory in LaLiga on Saturday.Real were in control of the game from early on but became frustrated as they wasted several clear chances before Polish striker Lewandowski silenced the Bernabeu crowd with a two-goal blitz after quick counter attacks in the 54th and 56th minutes.As Real tried to get back into the contest, Barca killed them off with two more goals on the counter as 17-year-old Lamine Yamal became the youngest Clasico scorer in the 77th minute and captain Raphinha wrapped up the win in the 84th.Barca extended their lead at the top as they moved to 30 points, six above Real and nine clear of Villarreal in third.