Andy Murray's reign as world No1 is under threat, says Roger Federer

• Federer warms up for Wimbledon campaign by reaching Halle quarter-finals• Marin Cilic emerges from chaos at Queen's to become title favourite Roger Federer, employing all the verbal dexterity he brings to any discussion on tennis, on Thursday lent his voice to the suggestion that Andy Murray's reign at No1 in the world is under serious threat for the rest of the summer. "Andy was tired after getting to No1 at the end of last year and then has been struggling with injuries," the 35-year-old...