MotoGP World Championship leader Jorge Lorenzo claims it will be ‘difficult’ to fight Fiat Yamaha team-mate Valentino Rossi in this weekends Italian Grand Prix at Mugello, but insists that isnt his main objective anyway. Lorenzo may be the only rider to have won two races so far this year, handing him a one point advantage over Rossi and Ducatis Casey Stoner heading into round five, but Rossi …