The Florence outfit suffered a 1-0 home defeat to Juventus on Thursday to crash out of the competition at the last 16 stage 2-1 on aggregate.
But Della Valle refused to criticise the club's players, citing David Pizarro's injury early in the second period as a turning point in the tie.
"The fans are proud of the guys," he is quoted as saying by Gazzetta dello Sport. "We tried.
"We were also unlucky, as Pizarro's injury made the difference."
Fiorentina visit Napoli in Serie A on Sunday and Della Valle is keen to see the team switch their focus back to the league.
"Now we go to Napoli and we keep the fourth place," he said. "We have another very challenging 10 days."
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