MIAMI • World No. 1 Novak Djokovic advanced to the fourth round of the ATP and WTA Miami Open, defeating Portugal's 38th-ranked Joao Sousa 6-4, 6-1.

The two-time defending champion needed only 78 minutes to win his 12th match in a row at the hard-court event and 26th in his past 27 Miami starts.

"That first set could have gone either way," Djokovic said.

"I managed to hit the right balls at the right moment and make it to the finish."

The 28-year-old Serb, who won his 11th Grand Slam crown at the Australian Open two months ago, also has titles at Doha and Indian Wells this year and hopes to complete the Miami-Indian Wells sweep for the third consecutive year.

His next foe will be Austrian 14th seed Dominic Thiem, who dispatched 124th-ranked Japanese qualifier Yoshihito Nishioka 6-2, 6-2 in 64 minutes.

"He has one of the most powerful baseline games in tennis," Djokovic said of Thiem.

"He's had one of the best years of his life. He's beaten Nadal on clay. He's one of the players we should all look out for."

Thiem captured his fifth career ATP title last month by beating Australia's Bernard Tomic in the Acapulco final and downed 14-time Grand Slam winner Rafael Nadal on the way to a Buenos Aires clay-court crown.

In the women's tournament, Australian Open champion Angelique Kerber and last week's Indian Wells winner Victoria Azarenka reached the last 16.

German second seed Kerber advanced 1-6, 6-2, 3-0 when 108th-ranked Dutch qualifier Kiki Bertens retired.

She next faces Hungary's 49th-ranked Timea Babos.

Eighth-ranked Azarenka eliminated Polish qualifier Magda Linette 6-3, 6-0.

Next up for her is Spaniard Garbine Muguruza.

Azarenka is trying to become only the third woman to take Indian Wells and Miami in the same year after Steffi Graf in 1994 and 1996 and Kim Clijsters in 2005.

AGENCE FRANCE-PRESSE

ATP MIAMI OPEN

Day 7, StarHub Ch201, 11pm