Saina Nehwal was made to sweat by American Beiwen Zhang before making it to the women's singles quarter-finals in the All-England Badminton Championships in Birmingham on Thursday night.
The seventh seeded Indian ace needed an hour to quell the challenge of the American qualifier 24-22, 18-21, 21-19 in a second round match.
The Commonwealth Games gold medallist next meets fourth seed Chinese Wang Shixian, who brushed aside the challenge of Ireland's Chloe Magee of 21-15, 21-12 in another second round match.
Saina, the only Indian left in the fray at the championships, said she was struggling to sleep properly because her room was cold.
Intanon eyes Xuerui showdown
Meanwhile, Ratchanok Intanon, the youngest ever World singles champion, moved within one win of a probable All-England Open showdown with Li Xuerui, the Olympic champion, before admitting her patchy form is scary.
The two women battled into the quarter-finals on Thursday, with the 19-year-old Thai coming from behind for the second day in succession and then producing a confessional about her mental state.
At one stage Ratchanok was a game and 11-11 down before getting past Han Li, the world No 19 from China, 18-21, by 21-14, 21-11.
The day before she was within three points of defeat against Singapore's Gu Juan.
Honing her survival instincts in this way despite a patchy performance may be crucial, as the seven months since she overcame Li in the World final have, she admits, been hard to handle.
"Everyone has been trying to beat me and I have been putting myself under pressure and been scared of the losses," said the Thai teenager.
"So I try to concentrate on practising. I try not to think about the World Championships because I am not the world No 1."
That, of course, is Li, who earlier made a great escape for the second successive day by coming from a game and 8-13 down against Minatsu Mitani, the world No 16 from Japan, also drifting to within three points of defeat before winning 14-21, 21-19, 21-15.
Image: Saina Nehwal
Photograph: Getty Images