SINGAPORE, Nov 7 (Reuters) - World number one Rory McIlroy has defended his decision to skip last week's WGC-HSBC Champions tournament in China to watch his girlfriend play tennis but admits that the criticism of his no-show was fair. The Briton returns to action at this week's co-sanctioned Singapore Open after taking a week off to cheer on Caroline Wozniacki at the Tournament of Champions in ...