The 32-year-old Cameroon striker has started life at Stamford Bridge slowly following his summer move from Anzhi Makhachkala, but scored twice in Wednesday night's 3-0 win over Schalke in Champions League Group E.
He netted his first Chelsea goal against Cardiff last month in a match remembered for his controversial, and illegal, steal of the ball as their goalkeeper David Marshall bounced it.
On that occasion he set up Eden Hazard - back for Saturday's match with West Brom after being omitted for disciplinary reasons from the Schalke match - but the Cameroonian was the sole beneficiary of his charge-down of Timo Hildebrand.
"Samuel is working very hard for us and I think for us it is very important that our strikers start to score goals and help the team a lot," Ivanovic said.
"Age doesn't matter - it is what he shows on the pitch. It is important to recover well, and to try to make the next games because Fernando (Torres) now is injured."
Torres, who is out for around three weeks with an adductor injury, scored twice against Schalke in Gelsenkirchen and Eto'o scored twice in west London before Demba Ba added a third to ensure all three of Chelsea's strikers have scored in two games against Schalke.
Eto'o has won the Champions League three times and was part of Jose Mourinho's winning side for Inter, who beat Chelsea en route to winning the tournament.
"It was very difficult to play against him," added Ivanovic, recalling the 2010 competition.
"In that moment he was one of the best strikers and I think he can be at the same level again.
"But the important thing is to play and to score goals for (the team).
"I think the first goal showed that he has a big wish to prove (himself) and to go forward. We know he has come here to help us."
Ivanovic agreed with the decision to drop Hazard, who Mourinho said will be in contention on Saturday.
"It is important for the team, but also Eden accepts this as a discipline and he will be in the next game," Ivanovic added.
"It means we are serious, and we are all together - and I don't think he has a problem with that."