Carreno-Busta was Djokovic's fourth-round opponent at the US Open last month when the world number one was defaulted for striking a ball that inadvertently hit a line judge.

It looked like the Spaniard might find a way past the Serbian again at Roland Garros as he took the first set, with Djokovic clearly troubled by an apparent injury to his neck and upper left arm.

However, he fought through that and triumphed 4-6 6-2 6-3 6-4 in three hours and 10 minutes to set up a last-four showdown with Stefanos Tsitsipas, which will be Djokovic's 38th grand slam semi-final.

It was clear something was not right with Djokovic early on given that, as well as wearing tape on his neck, he continued to stretch and hit his left arm while struggling to make first serves.

Carreno-Busta forged ahead for the first time when Djokovic netted a forehand on serve and, though the Serbian would hit back to make it 4-4, the Spaniard claimed a second break before serving out the opener.

Djokovic received treatment on his left triceps between sets and that seemed to have the desired effect as he levelled up the match with an authoritative forehand that saw him break to love.

The previously subdued world number one had rediscovered his mojo and reeled off three straight games to seize the initiative in the third set, only for Carreno-Busta to fight back and then miss a forehand winner that would have put him a break up.

It was Djokovic who stepped up when it mattered, too, an ace dispatched down the middle putting him one set from victory.

A tireless Carreno-Busta then miscued at the net on serve to give a 4-3 advantage to Djokovic, who staved off three break points before converting his first match point.