MELBOURNE – Andy Murray says winning the US Open and Olympic gold in 2012 will help him going into Friday’s Australian Open semi-final against Roger Federer.The Briton takes on the 17-time Grand Slam champion in the night session on Rod Laver Arena.The third seed believes that winning his first major title in New York last September, after beating Federer at London 2012 , has changed his outlook. “I feel probably a little bit calmer maybe than usual,” said the Scot.“But I still have an understanding of how difficult it is to win these events. With the players that are still left in the tournament, it’s going to be a very tough few days if I want to do that.”An 11th victory in 20 meetings against Federer - in a match to be shown live on BBC Two - would set up a final on Sunday against fourth seed David Ferrer or, more likely, world number one and defending champion Novak Djokovic.Federer, 31, remains a huge obstacle however, sweeping through the draw at Melbourne Park until he needed five sets to beat Jo-Wilfried Tsonga in the last eight.
