Djokovic had lost his two previous matches on clay in the European spring season, and his next opponent at the last warm-up event for the French Open is one of those players who's already beaten him.
In the quarter-finals on Thursday, the second-seeded Djokovic will play Matteo Arnaldi who earlier advanced past Fabian Marozsan 6-3 7-6 (7-3).Â
The Italian had defeated the great Serb in two sets at the Madrid Masters.
"My first win this season on clay obviously, it's great to break the ice in a way. It's a very demanding surface," Djokovic said on-court.
He faced no break-point chances, landed 73 percent of his first serves and clinched with a backhand winner on his second match-point chance,
"It helps if you have a good serve and today I think that was my strongest shot," Djokovic said.
The 24-time Grand Slam singles champion is seeking his 100th career title on the ATP Tour.
Geneva is a popular stop with players seeking more match practice before Roland Garros and No.4-ranked Taylor Fritz had lost his opening match at the Rome Masters this month.
Fritz, top-seeded this week, advanced to the quarters with a 6-4 7-6 (7-5) win over Quentin Halys of France.
He next plays sixth-seeded Hubert Hurkacz, who also won in two sets against a Frenchman, beating Arthur Rinderknech 6-4 6-1.
Fourth-seeded Karen Khachanov advanced because Kei Nishikori retired in the second set of their match held over from Tuesday because of the weather. Khachanov next meets Austrian qualifier Sebastian Ofner, who beat Nuno Borges 7-6 (7-2) 7-6 (7-4).
Meanwhile, in his home Hamburg Open, top seed Alexander Zverev blamed illness after he was humbled by Frenchman Alexandre Muller on Wednesday.
World No.40 Muller prevailed 6-3 4-6 7-6 (7-5) in the last 16 to stun the centre court in Zverev's birth city for perhaps the biggest win of his career.
"Given the fact that I threw up 37 times and had a fever of 39.4 degrees (Celsius) all night, it was actually quite okay," Zverev said.
"If it had been another tournament in a city in another country, then I certainly wouldn't have played."
