MIAMI (AFP) - Desperate Novak Djokovic fought back from a set and a break down to defeat Alexandr Dolgopolov 6-7 (3/7), 7-5, 6-0 on Tuesday, salvaging hopes of defending his Miami Open title.

World number one Djokovic won 24 of the last 27 points to reach a quarter-final against Spanish sixth seed David Ferrer, a 7-6 (7/5), 6-0 winner over Frenchman Gilles Simon at the ATP and WTA hardcourt tournament.

Ukraine challenger Dolgopolov was unable to stretch his lead to a double break in the second set, Djokovic saving two break points in the fourth game.

The Serbian top seed turned the match on its head in a 22-minute final set in which he could do no wrong, sustaining his chance for a US double after his Indian Wells final victory over Roger Federer.

Dolgopolov began breaking down in the third set after getting blisters on both feet taped. Near the end he was clasping at his thighs with cramps as he went down to defeat.

Japan's fourth seed Kei Nishikori beat Belgian David Goffin 6-1, 6-2 with Nishikori set to move to a career-best fourth in the world, sending Rafael Nadal to fifth.

Another quarter-final was set as Czech eighth seed Tomas Berdych advanced thanks to a mid-match withdrawal from France's injury-hit Gael Monfils. Berdych won 6-3, 3-2 when his opponent stopped a game after falling heavily on his right hip. Monfils has now withdrawn 15 times in his career.

"In the end I feel sorry for Gael. That's not the ideal way to finish up the match," Berdych said. "But in the end, I'm through. That's what matters. That's what counts.

Berdych will take on Argentina's Juan Monaco, a 6-3, 6-3 winner over Fernando Verdasco. Monaco will be playing in the last eight at the ATP Masters level for the first time in three years.

On the women's side, German ninth seed Andrea Petkovic ousted Czech 14th seed Karolina Pliskova 6-4, 6-2, in a quarter-final. Petkovic saved six of the eight break points she faced while breaking five times in the 75-minute victory.