Djokovic has been some way from his convincing best in an erratic season where he is bidding to win a record 25th Grand Slam title and the top-seeded Serbian was dragged into a battle by Carballes Baena after recovering an early break.
Having nosed ahead on serve in the ninth game, Djokovic set up break point with a big overhead smash after a 24-shot rally and pounced to take the first set as spectators on Philippe Chatrier sensed a return to a more familiar level.
"There's always conviction and belief inside of me that I can win a Grand Slam," Djokovic said after the match.
"That's the reason I'm still competing at this level. That's why I'm here.
"At this age, I wouldn't be competing at the Grand Slams and continuing to play professional tennis if I didn't believe I possess the quality to go all the way to the title match.
"I still of course sense that I have the game and I have the goods to go far."
Djokovic moved up a few notches in the next set for a 4-0 lead before his 31-year-old opponent even got on the board and the three-times Roland Garros champion tightened his vice-like grip on the contest in double quick time.
The pair's previous two encounters were both at hardcourt Grand Slams but the outcome was no different on Parisian clay as Djokovic sauntered ahead 5-1 in the third set and wrapped up the victory in style.
Despite the near-flawless display, Djokovic stressed that he would continue keeping expectations low as he prepares to battle Frenchman Gael Monfils or Italian Lorenzo Musetti.
"Of course, hopes and beliefs and convictions are always there, always high, and I always aim for the highest star," Djokovic said.
"I'm being conscious of the present moment and what needs to be done daily to build my form as the tournament progresses and then peak at the right time when it matters the most."
