Rory McIlroy confident of catching WGC-HSBC Champions leader Hideki Matsuyama

"I've been able to come back from six behind with 18 to play, so over 36 holes a lot of things can happen."

Rory McIlroy is confident he can overturn a six-shot deficit to the in-form Hideki Matsuyama and claim a fourth win of the year in the WGC-HSBC Champions in Shanghai.

World number three McIlroy managed just two birdies in an opening 71 at Sheshan International on Thursday to trail overnight leader Rikard Karlberg by seven shots.