Michael Olunga scored for Kashiwa Reysol in his final match before joining the Harambee Stars squad in France.
It was a vital win for Kashiwa Reysol against FC Gifu in the Japanese second-tier at the Sankyo Frontier Kashiwa Stadium.
Kashiwa Reysol are fifth on the log but could drop to sixth should Kyoto Sanga manage a win over Tokyo Verdy in their respective match.
They will next face Ehime on June 9 without their top scorer, Olunga, who is set to represent Kenya in the 32nd edition of the Africa Cup of Nations.
Meanwhile, coach Sebastien Migne has admitted that the France training camp will play a pivotal role as Harambee Stars prepare for two friendly matches against Madagascar and the Democratic Republic of Congo before leaving for Egypt.
"Our location here in France is favourable. The weather is good and the environment is also free of distractions. We are now working on getting everyone both physically and tactically ready for the Afcon,” Migne told the Football Kenya Federation's website.
The following players are yet to join the Harambee Stars camp: Victor Wanyama, Anthony Akumu, Ayub Timbe, Ovella Ochieng, Eric Johanna, Christopher Mbamba, Michael Olunga, Joseph Okumu, David Owino, Brian Mandela, Eric Ouma, Patrick Matasi, John Oyemba and Farouk Shikalo.