The Cameroon veteran opened the scoring for the visitors in the fourth minute and also struck four minutes before full time, his goals coming either side of Lukaku's strike on the half-hour mark.
Martinez told reporters after the game: "The mentality from Romelu Lukaku is that of a winner. He wanted to get us back in the lead and he took a knock to his toe but he wanted to continue. I am delighted with his performance and his personality.
"What Samuel Eto'o brings is incredible experience but with that is also a great hunger. He is a terrific example to have him around.
"He is a clinical finisher. He knows how to hurt back fours. He first touch is with the thought of what he is going to do next."
The result puts Everton ninth in the Premier League table.