The Swiss star came from a set down to beat Borna Coric in a nervy semi-final yesterday.
The win set up a showdown with Juan Martin del Potro – who is in fine form himself heading into the California decider having won the Mexican Open earlier this month.
Federer will be hoping to continue his career-best unbeaten run of 17 matches.
However, the 36-year-old has admitted that he does not expect to beat Del Potro to claim his third tournament win of 2018.
“It is another chance for a title and that would be amazing,” Federer told ATP World Tour.
“But I don’t expect it.
“I am just happy that I am injury free and playing as well as I am.
“To be winning the matches through fight and grit is a great feeling.”
Meanwhile, Federer also moved to thank the crowd at the BNP Paribas Open as he continues to be supported by sold-out arenas.
“I am enjoying myself, the crowds are amazing every time I show up on court,” he added.
“I really appreciate that.
“I don’t take it for granted at all.”