Roger Federer serves one against Nicolas Almagro in Key Biscayne on Monday

Miami: China’s Li Na continues her improved play while Roger Federer and Serena Williams have revenge on their minds following victories at the ATP/WTA Miami Masters Series event.

Li, the 15th seed, stunned the fourth-seeded Kim Clijsters 4-6, 6-4, 6-2, in the fourth round of the $6.9 million event.

Clijsters is perennially among the top players in the world. The Belgian has 34 career titles, including one at Sydney earlier this season, where she beat Li in three sets in the semi-finals.

That was Li’s third loss in as many career meetings with Clijsters. But she reached the round of 16 at the Australian Open and was a surprising semi-finalist at Indian Wells earlier this month — her best career showing at both events.

Clijsters became the second highly seeded woman in as many days to make an early exit. Fifth seed Martina Hingis was bounced Sunday.

Top seed Federer, whose 41-match winning streak was snapped by Guillermo Canas two weeks ago at the Pacific Life Open, will get his chance for revenge in the fourth round on Tuesday.

Federer, who is chasing a third consecutive Miami title, defeated Nicolas Almagro, 7-5, 6-3, dropping just five points on his first serve.

Canas, who is one of three qualifiers to reach the fourth round, defeated 15th-seeded Frenchman Richard Gasquet, 7-6 (7-3), 6-3.

In a night match, Serena Williams posted a 6-3, 6-4 victory over 23rd seed Lucie Safarova of the Czech Republic in a third-round match that was scheduled for Sunday night but was pushed back after rain and wind disrupted Sunday’s slate.

Seeded 13th in this Tier I hardcourt event, Williams will get a chance to avenge her sister’s loss as she set up a meeting with top seed Maria Sharapova.

Sharapova needed three sets and 2 1/2 hours to take out Venus Williams on Sunday.

Monday’s other fourth-round matches saw second seed Justine Henin and sixth seed Nadia Petrova advance but third seed Svetlana Kuznetsova was not as fortunate.

A native of Belgium and the top-ranked player in the world, Henin made quick work of 18th seed Vera Zvonareva of Russia, 6-3, 6-2.