Alexis Sanchez's superb first-half double helped give Arsenal a 3-0 win over Manchester United in a dominant display that propelled the London club into second place in the Premier League. Arsenal decided the game in the opening 20 minutes after a furious start at the Emirates. Sanchez's sublime backheel-flick at the near post opened the scoring in the sixth minute, and Mesut Ozil doubled the lead a minute later when coolly curled the ball home after being set up by Theo Walcott. Sanchez's second was a fierce shot from the edge of the area in the 20th after a quick Arsenal passing move. It was Sanchez's fifth goal in two league matches after his hat trick against Leicester last week. The Gunners leapfrogged United into second place with 16 points, two behind leading Manchester City. (For more sports news andupdates, followAhramOnlineSportson Twitter at@AO_Sportsand onFacebookatAhramOnlineSports.) http://english.ahram.org.eg/News/152083.aspx