They finished second in their group behind Congo with five points and can now look forward to a last-eight tie against the runners-up in Group B in Ebebiyin on Saturday.
"We only think of the next match and we are confident we will give our best no matter who we will face," said Balboa, the Real Madrid youth product now playing in Portugal who won and then converted the penalty that set the hosts on their way to a famous victory.
"Our power now is that we are a united team. In 2012, we had so many players who were not from our country and the fans were not happy about this and did not take as much pride as they now do about the national team," said Spanish-born midfielder Juvenal Edjogo-Owono.
Last summer they were disqualified from the competition for fielding an ineligible player in a qualifier against Mauritania, only to be reinstated as the replacement hosts following Morocco's withdrawal. That late decision, and the appointment of new Argentine coach Esteban Becker at the start of this month, left them with little time to prepare for the finals.
We knew we had to fight and the coach also told us that we have to fight not just for 90 minutes but for even more.
Juvenal Edjogo-Owono, Equatorial Guinea midfielder.
"Yes, we were together for about 20 days to prepare for this competition. But we had a dream," added Juvenal, whose side started with draws against Congo and Burkina Faso. "We knew we had to fight and the coach also told us that we have to fight not just for 90 minutes but for even more. That's what is important in football. We had to run more, we had to fight more. We gave everything we got against Gabon and deserved our victory. And now we are in the quarter-finals of the Nations Cup."
Meanwhile, Becker said he took a quick decision to do away with players with no links to the country.
"All the 23 players in my squad have links with Equatorial Guinea, whether their father or mother or grandfather was born in this country," said a proud Becker, who guided the country's women's team to win the 2012 African Championship on home soil. "This is very, very important."
Becker has maintained that he hopes to continue to work with a team who he believes has a bright future.
"This is the beginning of a new process, a team for the future. The focus remains this tournament and after that I would love to continue to work with this young team," he said.
Besides the more experienced campaigners like Juvenal and Balboa, the Nzalang Nacional can boast some exciting young players like 21-year-old goalkeeper Felipe Ovono, Kike Boula, who is also 21 and features for Real Mallorca in Spain, and the 19-year-old forward Iban Edu.
"The future of football in Equatorial Guinea is guaranteed because of these young players," assured Juvenal.