Daniil Medvedev made it into the Marseille ATP final after Aussie qualifier Matthew Ebden retired injured with their semi-final at 6-4, 3-0 in the Russian's favour on Saturday.
The top seed and world number three will face French 93rd-ranked Pierre-Hugues Herbert for the title.
Herbert, who put out two-time defending champion Stefanos Tsitsipas in the last eight, eased past compatriot Ugo Humbert 6-3, 6-2.
World number 287 Ebden left the court for a medical timeout after the first set, returning but with his movement clearly compromised.
"It's a real shame for Ebden," sympathised Medvedev, who will take the world number two spot from Rafael Nadal in Monday's latest ATP rankings.
"He's had a dream week with this semi-final from qualifying.
"And today, up to his injury, he was almost playing better than me."