The centre-forward, who is now the all-time top French goalscorer in international football, was an Arsenal player for several years.
Pochettino, who is without a job since leaving Paris Saint-Germain in the summer, admitted Giroud's goal scoring prowess always frustrated him.
“He was a player you face and you know was capable of everything. It's massive.
“It's a player, we as center-backs hated because he's a killer, inside the box it's difficult because he's big, clever - so smart."