Rory McIlroy wins PGA Championship at Valhalla . second straight major for world number three . Has to withstand challenge from PGA Championship pair Rory McIlroy and Valhalla . Tournament finishes in gloom after rain delay .
Rory McIlroy wins PGA Championship at Valhalla . Second straight major for world number one . Has to withstand challenge from U.S. pair Mickelson and Fowler . Tournament finishes in gloom after rain delay .