Sydney - Chelsea boss Jose Mourinho Tuesday rejected a report that star striker Diego Costa wants to quit the English Premier League champions.
A Spanish newspaper reported that the Brazilian-born Spanish international was homesick and had made contact with Atletico Madrid about a return to Spain.
Costa proved a handful before he tired and was substituted in the 40th minute of Chelsea's 1-0 win over Sydney FC in their final match of a long season in Sydney on Tuesday.
Mourinho said reports of Costa being unhappy with his lot at Chelsea were wide of the mark.
"I'm happy he's unhappy," Mourinho told reporters.
"He's the guy responsible for everything good we have in the dressing room. He's so happy, he's so funny, he's enjoying every minute. He makes people enjoy.
"He's the happiest guy in the dressing room, so if this is unhappiness, I'm happy with that.
"I think he was not happy with the news, and I think in his bad English he has to try and address that he's not happy with the news -- and not Chelsea."
Costa has been troubled by a recurring hamstring problem, and was not risked for the whole game in front of a capacity 83,598 crowd at Sydney's Olympic stadium.
"Diego was tiring and we didn't want to risk (it)," Mourinho said.
"I told him, 'Let's give to the fans at least half an hour of Diego Costa'. He went until minute 40 and in that time we all felt that was enough."