Li is also a crowd favorite in Australia, where she lost the finals last year to Victoria Azarenka and in 2011 to Kim Clijsters and has reached the semifinals four times in the last five years. Azarenka, the two-time defending champion, is in the other half of the draw.
Li won her only previous match against Bouchard in straight sets at Montreal in 2012.
"We had a tough battle last time, and I think I didn't have a lot of experience back then," Bouchard said. This time I think I'll be ready."
Li beat two 16-year-olds in the opening rounds and had to save a match point against Lucie Safarova in the third. Against No. 28 Pennetta, she was relentless, keeping the mistakes down while going for her winners.
"After saving the match point, I think I got a lot of confidence," Li said of her close call in the third round. "Even more belief in myself."
Li lost her serve just once -- while leading 5-0 in the opening set -- and finished off the 67-minute match with an easy forehand to the open court.
The Associated Press contributed to this report.