The Cameroon striker has appeared to lack his usual deadliness in front of goal in his two appearances since joining the Blues from Anzhi Makhachkala in the summer but Mourinho, who saw Eto'o score goals for fun at Inter Milan, believes he will find his rhythm quickly.
"When you are three, two and a half years in a place that doesn't motivate you, that you are out of the big stage, maybe you are there not for the right reasons, and you lose the hunger, the appetite," Mourinho said after Wednesday night's 2-1 Champions League loss to FC Basel.
"Now he (Eto'o) has that back, he has that motivation, he wants to succeed, he wants to play, he's happy to be at this level. The sharpness, that click to score, we have to wait. But he's a great player and he will score goals."