Moses and Mikel were both at the Africa Cup of Nations - playing for eventual winners Nigeria - but are now back with the Blues and are expected to play some part at Stamford Bridge.
"I think they will come back with more confidence, more belief and it has to be good for the team," the Chelsea interim manager said.
"It's important to have happy and confident players around, so it's good for the team that they won and they've brought that confidence and belief back with them.
"Both of them progressed as individuals through the tournament.
"Obi has more experience and you could expect good performances from him, but Victor was coming through and I could see he has been growing and improving.
"I am really pleased for both of them, and to be so influential is a great achievement for Victor."
Also available for the west London derby are David Luiz and Demba Ba, who missed Thursday's Europa League last 16 clash with Sparta Prague through suspension and being ineligible respectively plus John Terry who has recovered from a knee injury.
"We have now more options that we didn't have before," Benitez added. "It's a great advantage if you want to give minutes to players, play with fresh legs. It can help to keep a higher tempo during the game.
"The team has won two games in a row (against Sparta and Wigan last weekend) and has to be much better now in terms of how to approach the game (with Brentford), with confidence.
"Brentford will try to be compact and counter-attack, and we are favourites and will try to do a professional job.
"From the first minute we have to push and push and try to win."