Back on court for the first time since the birth of his son, Jo-Wilfried Tsonga was upset by a qualifier in the second round of the Monte Carlo Masters on Tuesday.
The seventh-seeded Tsonga lost to fellow Frenchman Adrian Mannarino 6-7 (3), 6-2, 6-3 at the first big tournament of the clay-court swing.
A two-time semifinalist at the Country Club, Tsonga had not played since losing his opening match to Fabio Fognini at Indian Wells in early March. Tsonga then took time off following the birth of his first child Shugar on March 18.
The 10th-ranked Tsonga led 3-0 in the first set then struggled to cope with the good mix of baseline shots and slices from Mannarino.
Mannarino broke Tsonga six times and will next go against Lucas Pouille or Paolo Lorenzi.
Back from an elbow injury, two-time champion Novak Djokovic later started his campaign against Frenchman Gilles Simon.