By Larry Fine
NEW YORK (Reuters) - Li Na notched another pay-back victory at the U.S. Open, beating former world number one Jelena Jankovic 6-3 6-0 to advance to the quarter-finals on Sunday.
The fifth-seeded Chinese, who overturned last year's defeat by Laura Robson by beating the Briton in the third round, snapped a four-match losing streak to the Serbian dating back to Paris in 2009.
Former French Open champion Li cracked 20 winners and conceded only 12 unforced errors in a dazzling display, converting all her seven break points in a 57-minute masterclass.
"The last time in Rome I lost in two sets straight away. She plays pretty good defense, but who knows, maybe I played the best match of my whole life," Li said with a chuckle in her on-court interview.
"I still remember last time I played her in Rome. I was feeling I played pretty good, but still lost the match," she told reporters. "So I was so sad after the match."
Li said her coach Carlos Rodriguez used that defeat to motivate her.
"Before this match, Carlos didn't tell me anything. Just said, 'remember how you felt after that match.'
The victory put 31-year-old Li, Asia's first grand slam singles champion, into the U.S. Open quarter-finals for the second time following her trip to the last eight in 2009.
A two-time Australian Open finalist, Li next faces Russian 24th seed Ekaterina Makarova, who upset third seed Agnieszka Radwanska 6-4 6-4.
"Tonight she played really well, at a very high level," Jankovic said of Li. "I did not control the points. I let her do all the talk on the court.
"If she continues to play like this I think she can win the tournament."
(Reporting by Larry Fine; Editing by Ian Ransom)