Dominic Thiem. Pic/AFP

Austria's fifth seed Dominic Thiem fought back from two sets down to overcome American qualifier Denis Kudla and fierce heat to reach the third round at the Australian Open on Thursday. Thiem looked headed out the door before he turned around the match in the third set and went on to complete a 6-7 (6/8), 3-6, 6-3, 6-2, 6-3 victory in 3hr 48min on Margaret Court Arena. In searing on court temperatures, Thiem wore down the 190th-ranked Kudla to set up a third round match against Czech Jiri Vesely or French 26th seed Adrian Mannarino. "It's awesome. It's only the second time in my career I've come back from two sets down and especially in this very hot weather it was tough," Thiem said.