Andy Murray fired up for singles return and confident he can challenge rivals

• Comeback continues at pace with positive doubles displays
• Murray: ‘I’m sure that, tennis-wise, I will be able to keep up’Andy Murray sees no reason he cannot still beat Novak Djokovic, Rafael Nadal and Roger Federer, the champions who have been part of his own history, as he continues a comeback that looked out of the question six months ago.He is back where he feels most comfortable in the entire tennis landscape, the second week of Wimbledon – even if only