Li Na notched another pay-back victory at the US 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 US 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."
Poland's third seed Agnieszka Radwanska has been bundled out of the US Open by Russia's Ekaterina Makarova in the biggest shock of the women's event at Flushing Meadows.
Makarova struck a barrage of groundstroke winners to topple Radwanska 6-4 6-4 in the fourth round under floodlights on Louis Armstrong Stadium.
Radwanska started brightly, surging to a 4-0 lead, but Makarova peeled off eight straight games to take the first set and lead 2-0 in the second.
Radwanska fought her way back, holding four break points to level the second set at 4-4.
Makarova, the 24th seed, sealed the game with an ace before going on to close out the match in one hour and 32 minutes.
Her next opponent will be China's Li Na after the fifth seed defeated Serbia's Jelena Jankovic 6-3 6-0 on Arthur Ashe Stadium's center court.
The 25-year-old Russian will play her first quarter-final at the US Open after twice reaching the last eight at the Australian Open.
"It feels amazing, I really love this tournament," she said.
Radwanska's loss left her out of the quarter-finals at a major for the first time this year.
Top seed Novak Djokovic roared into the fourth round of the US Open with a 6-0 6-2 6-2 victory over Joao Sousa of Portugal under the lights of Arthur Ashe Stadium on Sunday.
The 26-year-old Serb, who has yet to lose a set, smacked 34 winners to just 10 for the 95th-ranked Sousa in the 100-minute rout.
Australian Open champion Djokovic faced just two service breaks, while converting eight of 13 against his opponent.
Serena Williams avenged her loss to Sloane Stephens earlier this year by thrashing her fellow American in straight sets on Sunday to reach the quarter-finals of the US Open.
The world number one showed no mercy against Stephens, crushing the rising star 6-4 6-1 to remain on course to defend the US Open title she won last year and restore the sport's world order.
"How excited are we about the future of American tennis?" Williams asked in a courtside interview. "It definitely felt like something bigger."
Stephens beat Williams in January in the quarter-finals of the Australian Open to enhance her reputation as one of the leaders of the next generation but was outgunned on Sunday.
The 31-year-old Williams, bidding to become the oldest woman to win the US Open since tennis turned professional in 1968, won a tight first set then ran away with the second.
"Obviously she's number one in the world for a reason," Stephens said. "I thought she played really well.
"Obviously it didn't go how I wanted. The second set got away from me a little bit. All in all I thought I competed well and played well. That's all you can do really."
Williams advanced to play Carla Suarez Navarro in the quarters after the Spaniard upset Germany's eighth-seed Angelique Kerber 4-6 6-3 7-6(3).
RUTHLESS PLAY
The defending men's champion, Andy Murray, was also in a ruthless mood against Germany's Florian Mayer, winning their third round match 7-6(2) 6-2 6-2 in less than two hours.
Murray struggled to impose himself on Mayer in the opening set as both players tried to adapt to the gruelling conditions at the Arthur Ashe Stadium center court.
It was hot and steamy and the wind was gusting but once Murray found his rhythm it was all smooth sailing. The defending champion won the first set tiebreaker then broke Mayer's serve four times to close it out in straight sets.
"It was tough conditions, not tricky. It was very, very humid," Murray said.
"I was struggling breathing for most of the match."
Murray's opponent in the fourth round will be Uzbekistan's Denis Istomin, who beat Italy's Andreas Seppi 6-3 6-4 2-6 3-6 6-1, with Tomas Berdych looming in the quarter-finals.
Berdych, seeded fifth, made the semi-finals at last year's US Open and has been in great form at Flushing Meadows this week, reaching the last 16 without dropping a set.
The Czech dispatched Julien Benneteau of France 6-0 6-3 6-2 to set up a fourth round clash with Switzerland's Stanislas Wawrinka, who defeated Marcos Baghdatis of Cyprus 6-3 6-2 6-7(1) 7-6(7).
"Today was good," Berdych said. "It was a bit hot, a bit humid, but otherwise tennis was good.
"Finally, I managed to stay focused from the first point till the last. I didn't do any ups and downs, just took all my chances that I had and won in straight sets."
HEWITT PREVAILS
Australian Lleyton Hewitt continued his run through the draw when he beat Russia's Evgeny Donskoy 6-3 7-6(5) 3-6 6-1.
Hewitt won the US Open 12 years ago but the 32-year-old has turned back the clock this week to reach the last 16 for the first time since 2006.
Bob and Mike Bryan's bid to achieve a rare calendar-year grand slam in the men's doubles remained intact after they survived a tough center court clash.
The American twins switched sides after dropping the first set then found themselves down a break in the second before rallying to beat Canadians Daniel Nestor and Vasek Pospisil 6-7(1) 7-5 6-2.
"It ended up working out but it was just a desperate call," said Bob Bryan.
"We were feeling a little bit hopeless on the return games, and throwing in a switch like that sometimes is a psychological advantage."
The Bryan brothers have already won each of the last four grand slam doubles titles, starting with last year's US Open, but are bidding to claim all four in the same calendar year.
The only men to have achieved the feat were the Australian pair of Ken McGregor and Frank Sedgman in 1951.