Novak Djokovic registered a 6-2, 7-6(4) win over German lucky loser Mats Moraing on Tuesday in his opener in Belgrade where the World No. 1 is warming up for the French Open.
The clay-court Grand Slam starts in Paris on Sunday, and Djokovic opted for extra match practice on home soil this week.
The 34-year-old was made to fight by the World No. 253 before winning in an hour and 40 minutes.
It was Djokovic's first match since losing the Italian Open final to Rafael Nadal nine days ago.
He will next face Argentinian Federico Coria, the younger brother of former Roland Garros runner-up Guillermo Coria, in the quarterfinals.
The results (second round): Novak Djokovic bt Mats Moraing 6-2, 7-6(4); Federico Coria bt Pablo Cuevas 6-3, 6-2.