World No.6 Li Na says hot conditions made breathing difficult during her first-round win at the Australian Open on Monday.
The 2011 runner-up completed her 6-3 6-1 victory over Kazakhstan's Ksenia Pervak in one hour and nine minutes at Melbourne Park.
Li, 29, said she was lucky to breeze through the second set, after struggling to deal with temperatures above 30 degrees.
"I was feeling, at the end of the first set, really hot on the court. Also, I was feeling no air. I couldn't breathe," Li said.
"I was feeling like, 'What's going on?'. But (I was) so lucky to win so easy in the second set."
Li will go into her second round match against Australian Olivia Rogowska, the world No.168, as a hot favourite.
While she is hopeful of going one better than she did at the tournament last year, Li - runner-up to Victoria Azarenka at the Sydney International on Friday - said there is still a long way to go.
"I wish I can do better in this year, but I'm still far away," she said.
"I was happy with what I'm doing at Hopman Cup and Sydney. I think I just (need to) continue."