Five-time champion Serena Williams was sent crashing out of the Australian Open by little-known Russian Ekaterina Makarova Monday, as Andy Murray had no trouble reaching the quarter-finals.

An out-of-sorts Williams struggled through the first set and dished up a host of errors as she was well beaten 6-2, 6-3 by the world number 56, who has never won a title and is now into her first grand slam quarter-final.

Serena Williams at Australian Open. Pic/AFP.

China's Zheng Jie was also beaten 6-2, 6-1 by Italy's Sara Errani to end the country's singles interest on Chinese new year's day -- and a day after Li Na's tearful defeat to Kim Clijsters.

Williams's exit blows a giant hole in the women's draw with Wimbledon winner Petra Kvitova and Maria Sharapova, the 2008 champion in Melbourne, among the potential beneficiaries on her side of the draw.

Defending champion Clijsters also suffered an ankle injury during her win over Li which could hinder her progress.

Earlier Murray took the easy route to the last eight when Kazakhstan's Mikhail Kukushkin retired injured.

Under blazing sun Murray, seeking Britain's first grand slam title since before World War II, was always in command and he led 6-1, 6-1, 1-0 when Kukushkin pulled out with a hip muscle injury on 49 minutes.