South Korean tennis star Chung Hyeon is once again up against world number one Roger Federer in the quarterfinals of the Indian Wells Masters in California.<br /> The match started about an hour ago and is on set 2 as we speak,... with Federer finishing his service game with an ace leading 6-5.<br /> The match comes just under two months since Chung Hyeon had to retire from his Australian Open semifinal against Federer.<br /> And depending on the outcome of the match, the Swiss legend might have to step down from his title of 'world number one.'<br />
