Melbourne: Kim Clijsters was courage personified as the defending champion shook off a painful ankle injury and saved four match points to overhaul China's Li Na 4-6, 7-6, 6-4 and reach the quarter-finals of the Australian Open on Sunday.   

The big-hearted Belgian rolled her left ankle at 3-3 in the first set on a scorching day at Rod Laver Arena but rejoined the battle after a lengthy medical time-out with her foot thickly taped.   

In a re-match of last year's finalists, champion Clijsters stared at the abyss when 6-2 down in the second set tiebreak but reeled off six points in a row to take the set and spark a rapturous ovation from the stands.   

The hard-hitting Li slumped to 4-0 down in the decider then recovered gallantly to trail 5-4 but Clijsters held to close out the match and keep her hopes alive of a fifth grand slam title in her farewell year on tour.   

Clijsters next plays the winner of top seed Caroline Wozniacki and former world number one Jelena Jankovic.