Stefanos Tsitsipas reached the second round at the Monte Carlo Masters on Monday after Laslo Djere of Serbia retired with an injury when Tsitsipas led by 6-3, 3-2.
The Greek 12th seed won back-to-back titles in the Principality in 2021 and 2022 but was eliminated at the quarterfinal stage last year. Tsitsipas next faces the winner between Nicolas Jarry of Chile or Tomas Etcheverry of Argentina in the round of 32.
"Things are looking good. I am hoping to go the same way," Tsitsipas said. "I really enjoyed getting a better consistency on my serve towards the end. I hope to keep mixing it up and coming up with fun plays."
Frenchman Ugo Humbert continued his impressive season with a comeback 4-6, 6-1, 6-2 win against Federico Coria. The world No.15 has already pocketed two tour-level titles this year, triumphing in Marseille and Dubai.
Next for Humbert will be either Zhang Zhizhen of China or American Marcos Giron.
Felix Auger-Alisassime progressed to the second round by moving past Italian qualifier Luca Nardi 6-2, 6-3. The Canadian will play against third seed Carlos Alcaraz next.
Two-time Grand Slam winner Alcaraz received a first-round bye at the first clay Masters event of the season.
Miami Open finalist Grigor Dimitrov defeated wild card Valentin Vacherot 7-5, 6-2 in the first round. The ninth seed will next face Matteo Berrettini or Miomir Kecmanovic.