Li Na causing major upset in Sydney as Clijsters falters

China's Li Na is on course to win one of the biggest tournaments of her career and also take the scalp of Aussie Open favourite Kim Clijsters. She is using power and acuracy to help her attack the Clijsters second serve and after a slow start where she was 3-0 down, Li Na took the first set on a tie-break and leads 4-1 in the 2nd. Can Clijsters mount a comeback?