The Eagles fell to the Fennecs in a semi-final of the 2019 Africa Cup of Nations (AFCON) with Riyad Mahrez scoring the winning goal with a last-mite free-kick.
With the win, the Algerians will be playing Senegal in their first final in the competition since 1990 when they won it on home soil.
Belmadi who spoke after the clash, admitted that it got tough after Nigeria scored an equalizer.
“The guys made an amazing first half. We deserved to score more,” Belmadi told Caf website.
“In the second half we had a difficult moment for around 15 minutes where we were under pressure.
“After the penalty my players showed great attitude and mental strength and coming back until the end, fighting to score a goal was great for us.”
Algeria will play Senegal in the final of the biennial tournament at the Cairo International Stadium on Friday.