The first leg of the encounter had ended 1-0 in Ajax’s favour, meaning the English side advanced based on the away-goal rule.
Speaking after the clash on Wednesday, Moura said the coach’s talk to the team after the first half was instrumental to the win.
“In the changing room, the gaffer said we need to score one goal,” he told Spurs TV.
“If we score one goal we are in the game and when I scored the first, it gave us a lot of motivation to keep working and to keep fighting.
“After the second one, that’s football, everything is possible and we needed to believe.
“I always say that we need to believe and I believed.
“If we play like this, everything is possible.”
Tottenham will face Liverpool on June 1 in an all-English final in Madrid.