Novak Djokovic has come from a set down to defeat Alexandr Dolgopolov 6-7 7-5 6-0 and reach the quarter-finals of the Miami Open.

Both players surrendered serve twice during a close first set, which the Ukrainian edged in a tie-breaker when the defending champion sent a backhand long.

Things looked bleak for Djokovic when his opponent stormed into a 4-2 lead in the second, but the Serbian registered an immediate response before securing a crucial break to go 6-5 up and serve out the set.

The world number one was unstoppable in the deciding set, winning 24 of the 27 points on offer to secure victory and set up a quarter-final against David Ferrer.