Speaking in the embargoed section of his pre-Brighton press conference, the Manager discussed the recent return of last season's top goalscorer, who knows how to perform against Palace's rivals.
Sage recalled Ismaïla Sarr back into his starting line-up for the first time this season for the midweek defeat in Lyon.
The Senegal forward was withdrawn midway through the second-half, but Sage believes he could now be ready to complete a full 90 minutes.
Sarr has an excellent record in Sunday's fixture. He scored the only goal in Palace's visit to the Amex Stadium last season, and scored two and created another in a 3-1 win the year before.
"The first step for him was to play [off the bench], the second step was to start," said Sage.
"Now the third step will be to play the entire game. In each step, there has to be a good level of performance and with minutes he will come back [to his best].
"You have to be aware that he didn't train too much during all the summer, and the more time he has [on the pitch] it will be good.
