Djokovic, Sharapova battle into last 16 in windy Miami

(CNN) -- Novak Djokovic and Maria Sharapova progressed to the fourth round of the Miami Masters on Sunday, neither impressed with their form as they battled windy, hot conditions.

Djokovic, seeking to emulate Andre Agassi -- the only man to win at Key Biscayne three years in a row, from 2001-03 -- beat 254th-ranked Indian Somdev Devvarman 6-2 6-4.

"It was very difficult to kind of get into a rhythm because you couldn't really serve at 100% and you had to go more for precision and put twice as much effort into the step adjustments because of the windy conditions," said the world No. 1, who will next face veteran German Tommy Haas in the 10-day hard-court event.

"All in all, I'm just happy to get through the rough day."

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Djokovic, seeking his fourth Miami crown, having also won in 2007 as well as losing the 2009 final, was joined in the last 16 by Spanish third seed David Ferrer, who will next play Japan's No. 13 Kei Nishikori.

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The Australian Open champion's fellow Serbian Janko Tipsarevic, the seventh seed, will next face French No. 11 Gilles Simon.

Sharapova has been in four title matches in Miami, including the last two, and come away emptyhanded every time.

She is seeking to become only the third woman to win the Indian Wells/Miami double in the same season, and kept alive her hopes with a 6-4 6-2 win over fellow Russian Elena Vesnina, the 29th seed.

"It wasn't easy for the both of us with the heat and the wind," said the world No. 2, who is seeded third.

"It was just one of those days where you know you might not be playing your best tennis -- I certainly wasn't today.

"But I got through, and I'm onto the next one."

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Sharapova will next face 21st-seeded Czech Klara Zakopalova, who upset another Russian when she beat No. 14 Maria Kirilenko 6-2 7-6 (7-4).

Sharapova lost to the 31-year-old when she was just 15, back in 2003 at the Australian Open, but has won their last four meetings including a last-16 match in Qatar this year.

Romania's Sorana Cirstea earned a clash with former world No. 1 Jelena Jankovic after eliminating German sixth seed Angelique Kerber 6-4 6-0.

"I didn't have any expectations coming into this tournament because I've never played that well in Miami," the Romanian 28th seed said.

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"But I've been fighting the best I could and working my way through every single match, and it's working."

Jankovic, the 2008 runner-up, beat Russian 11th seed Nadia Petrova 7-6 (9-7) 6-4.

Alize Cornet ended the hopes of 19-year-old American Lauren Davis, who was allowed into the main draw when second seed Victoria Azarenka pulled out due to ongoing ankle problems.

The French 32nd seed came from behind to win 2-6 6-3 6-2 and earn a clash with either Italian Roberta Vinci or Spain's Carla Suarez Navarro.