The Pumas ended a 35-year wait for a victory over the Wallabies on Australian soil by grinding out a 23-19 triumph on the Gold Coast.
It marked the first time Argentina has won two matches in the same Rugby Championship and Ledesma was thrilled with the effort on display.
"I thought we were lacking a little bit of belief because I thought we could have scored more, and then it looked like we didn't want to win the game," he said.
"But they've been working their backsides off and this win is [because of] them.
"It's really difficult because we travel more than any other team, not only here but in Super Rugby as well. It's tough to keep that motivation going, but they do it and it's a pleasure to work with them."
Argentina's victory cranks up the pressure on Australia coach Michael Cheika, under whom Ledesma worked as part of the Wallabies' backroom team.
Ledesma added: "That's my team too, so it's difficult."