Daria Kasatkina reached her first Grand Slam semi-final with a 6-4 7-6 (7-5) win over Veronika Kudermetova in the French Open quarter-finals.
Kasatkina, 25, took the first set against the run of early aggressive play from her fellow Russian.
Both players traded breaks of serve in an edgy second set but 20th seed Kasatkina overcame her nerves to win on her fifth match point with a drop shot.
Kasatkina will face either Iga Swiatek or Jessica Pegula in the last four.
"You could see the match was really nervous and tight, especially the tie-break, but I am happy at the end I won," Kasatkina, the 2014 junior champion, said in her on-court interview.
"It's a very important win for me and I'm happy to be in the semi-final for the first time."
Kasatkina, playing in her third Grand Slam quarter-final but first since 2018, has made the last four without dropping a set.
Kudermetova was in her first Grand Slam quarter-final and made 50 unforced errors as she struggled to adapt to the occasion.
The 25-year-old needed a medical timeout at 5-6 in the second set but battled hard to save four match points in the tie-break.