Champions League: Both matches are tied. Arsenal have an away goal. They need to win or hold Villarreal scoreless. They have allowed two goals in 12 home matches since Christmas. They have not conceded in four Champions League home ties. Porto have two away goals. Man U need to score three goals or win outright. No English team has ever won at Porto. Elsewhere: Obama is backing the U.S. World Cup bid with a hand-written letter to Sepp Blatter, recounting his love for soccer as a child. A story about his mother’s stockings may have been more effective. And Guardian columnist Steven Wells discusses American blogger hatred for Tommy Smyth.  Proves only that he is enough of a misanthropic bastard to skewer a harmless old man in an international forum.