Denayer came on as a second half substitute to fill a gap in central defence after Vincent Kompany was sent off.
Kompany is a teammate of Denayer not only for Belgium but Manchester City, who have loaned him to Celtic for the season.
His impressive performances earned him a call-up for his country, and they have not gone unnoticed at City either.
Patrick Vieira, head of the club's elite development squad, used his twitter feed to reach out to Denayer after the game.
Congratulations to @Jasondenayer on his first cap for Belgium. The feeling of pride when you play for your national team never leaves you— Patrick Vieira (@OfficialVieira) March 31, 2015
It's a clear sign Manchester City are monitoring Denayer's progress closely, and his progress to international level is likely to encourage them.
This is bad news for Celtic's aspirations to keep the centre-back, who also impressed in the Europa League at the San Siro against Inter Milan.
The Manchester Evening News reported last week that City are keen to utilise Denayer next season.
From a Celtic perspective, Denayer's appearance in the 1-0 away win for Belgium was also notable as it saw him go up against Israeli midfielder Nir Biton, who had recovered from injury to start the game.