Bidding for an outright record seventh men's title in Miami, top seed Djokovic survived a brief scare to get past Delbonis 7-5 4-6 6-1.

Djokovic gave up leads in the first and second sets, but the world number one made no mistake in the third, finishing the match with 12 winners and 19 unforced errors.

The 15-time grand slam champion was growing increasingly frustrated before settling to move into the last 16, where Roberto Bautista Agut awaits.

Djokovic appeared in control early on despite giving up a break lead in the first set, taking the opener when Delbonis netted a forehand after being cramped for room.

He stormed into a 3-1 lead in the second set, only to lose four straight games, belting a ball away and smashing his racquet after double-faulting to fall 4-3 behind.

Delbonis saved three break points in the eighth game and then served the set out to love as Djokovic's agitation became even more apparent. 

Perhaps slowing his own momentum, Delbonis needed treatment on his left foot – already taped due to an apparent blister – after levelling the match.

For the third time, Djokovic took a 3-1 lead in the third set, a bad volley miss and double fault from Delbonis opening the door for the Serbian.

A backhand cross-court winner helped set up another break for Djokovic, who lost just 12 points in the final set as the Argentinian's level dropped.