The Australian Open women’s draw was thrown wide open Monday after Russia’s Ekaterina Makarova shocked Serena Williams in the fourth round, as Wimbledon champion Petra Kvitova won in straight sets.

Makarova, the world number 56, reached a grand slam quarter-final for the first time when she stunned a below-par Williams 6-2, 6-3 and will now face former champion Maria Sharapova, who battled back from a set down to progress.

But almost from the first point it was obvious that Williams, who suffered an ankle injury this month in Brisbane, was not her usual self as mistakes came thick and fast from her racquet, 37 in all.

The 30-year-old sent down seven double-faults as she was broken five times, ending a 17-match unbeaten streak at Melbourne Park stretching back to 2009.