Darren Mackie's first-half diving header gave them the away goal that carried them into the group stages with a 1-1 draw in Ukraine.
Dnipro levelled when a clearance cannoned off Andriy Vorobey and into the net with 15 minutes left and the Dons survived a late onslaught with Dnipro hitting the bar three times in the second period.
The triumph over a side sitting second in the Ukrainian league came in the week Rangers beat French champions Lyon and Celtic conquered holders AC Milan in the Champions League.
And Calderwood was delighted to continue the run with the first-round victory over a team brimming with Ukraine internationals.
He said: "I took Dunfermline to the Scottish Cup final and into Europe and then Aberdeen into Europe.
"But winning against a team of this quality is definitely the biggest achievement of my career.
"In the group I don't think we will face two or three teams as good as Dnipro. Maybe one but there won't be may as good as this team.
"It's a great result for Scottish football and a great result for us.
"Our coefficient will be going up and maybe we might get another team in the UEFA Cup.
"Five out of the league wouldn't be too bad."