Oct 24 (Reuters) - American Luke Guthrie left a quartet of former world number ones trailing in his wake with a blistering start to the BMW Masters in Shanghai on Thursday, firing a seven-under 65 to sit three shots clear of compatriot John Daly. The 23-year-old, who turned professional last year, had only 19 putts in his bogey-free round which was boosted by an eagle at the par-five 15th when he holed a flop shot from the bank by the green after chipping in for birdie on the previous hole. ... More...