The 26-year-old striker bagged both goals in the first leg as the Africa Cup of Nations winners secured a valuable 2-1 win, but he insists his side will face a sterner test on Saturday.
"The game in Calabar will be tougher for us than the one in Addis Ababa. We have to be careful and get ready for another big business in Calabar," Emenike told FIFA.com.
"Ethiopia are very good and they will be coming here with more tricks. So, we shouldn't see the first victory as the end of road."
While Emenike has warned his teammates about Ethiopia, the striker is quietly confident about Nigeria's chances of qualifying for Brazil 2014.
"I am glad to have played in the Nations Cup and won but I am dreaming of playing in my first World Cup for Nigeria," Emenike said.
"That will be the first time I will be at the World Cup and to get to play in Brazil, where they are crazy about football, would be a dream come true."
The Fenerbahce forward has rejected comparisons with Rashidi Yekini, a legend of Nigerian football who holds the country's all-time international scoring record of 37 goals.
"Rashidi Yekini's shoes are still too big for me to wear. I am only trying to do what I know is best for my fatherland, and I have not done anything yet," Emenike said.
"I still have a lot to do to get to the heights reached by such a legend."
Emenike has scored nine goals in 18 appearances for Nigeria since making his debut in 2011.