Eugenie Bouchard’s hopes of reaching her first WTA Tour final in two and a half years were dashed by injury in Gstaad.
The former world number five, who is now down at 146 in the rankings, trailed top seed Alize Cornet 7-6 1-0 when she was forced to retire with a groin injury.
Bouchard told wtatour.com: “It happened in the second point of the match.
“I felt stress or pain in my groin. But it was getting continually worse and really hampered my movement.”
Cornet took the first set tie-break 7-5 and broke the Canadian in the first game of the second set before the 24-year-old decided to concede defeat.
The Frenchwoman will play Mandy Minella in the final after the 32-year-old Luxembourg veteran came from a set down to beat Marketa Vondrousova of the Czech Republic.
Minella dropped her first set of the tournament against the world number 104 but hit back to triumph 4-6 6-2 6-2 and book her place in the first WTA Tour final of her career.
Fourth seed Petra Martic denied Romanian hopes of a home favourite reaching the final of the Bucharest Open.
Martic beat second seed Mihaela Buzarnescu 6-4 6-4 to advance to the final where she will play Anastasija Sevastova, who won the first set over Polona Hercog 6-1 before the Slovenian retired injured.