Venus Williams beats Radwanska to continue Melbourne fairytale

The 34-year-old prevailed 6-3 2-6 6-1 and will face fellow American Madison Keys in the last eight - if she wins that match, she could meet sister Serena Williams in the semi-finals.

Venus, a seven-time Grand Slam winner, has never gone further than the semi-finals in Melbourne. In recent years age and illness have slowed her down, and she had not reached the last eight of a Grand Slam competition since the 2010 US Open.

The 34-year-old, who suffers from Sjogren's syndrome, an auto-immune disease that can cause fatigue, was forced into a lengthy baseline battle with one of the best retrievers in the women's game.

Williams, however, put pressure on Radwanska's serve throughout, illustrated by the seventh game of the first set which lasted 15 minutes with the score locked at deuce 12 times before the American converted her sixth break point.

Radwanska appeared to have taken Williams' legs out from her in the second set before the 18th seed found a second wind in the decider, jumping out to a 4-1 lead as the Pole's accuracy disintegrated, then breaking to love and serving out to set up a quarter-final against fellow American Madison Keys.

She said of the 19-year-old Keys in her post-match interview: "She started watching me when she was in diapers. She's a wonderful player but of course I'll want to win."