Leg cramps forced Garbine Muguruza to retire at Australian Open from her Brisbane International second-round clash on Tuesday. The world No.2 led Serbia's Aleksandra Krunic - ranked 51 spots lower than the Spaniard - 7-5 6-7 (3-7) 2-1 in an encounter before collapsing to the ground in tears clutching her leg. Garbine admitted she was unsure of her next move after pulling out of the Brisbane tournament : "But I think I'm going to evaluate what options do I have now... maybe just go right away to Melbourne." The young woman Spaniard was forced to withdraw from the Brisbane tournament for the fourth year due to injury. Muguruza said she felt her calves tightening early in the second set. The match was over after she fell to the ground in agony grabbing her leg while attempting to make a backhand return. She received medical treatment before deciding to surrender. So Krunic became the first through to the Brisbane quarterfinals.