Rune (70th in the world) was down 4-3 in the first set when his opponent (40th) retired after feeling chest pain.
He is the first Danish winner of an ATP trophy since Kenneth Carlsen in 2005.
His great feat of the week, during which he did not give up a single set, was to beat the German Alexander Zverev (N.3) in the second round.
© 2022 AFP