Emma Raducanu was bundled out of the Citi Open in a 6-4 6-3 semi-final defeat to Anna Kalinskaya.
The British No 1 matched the Russian early, using her superior serve to pick up five aces in Washington.
However, she was frequently unable to take full advantage of her firepower as she failed to convert any of her four break point opportunities.
This left enough of a window for Kalinskaya to capitalise, clinching the first set before cruising through the second and wrapping up the victory in one hour and 34 minutes.
"It was an interesting match. It's nice to play against Emma," world No 48 Kalinskaya said, who has set up a shot at her first WTA Tour title. "I'm proud of myself. I stayed aggressive and stuck to my plan."
Kalinskaya will play Leylah Fernandez in Sunday's final after the the Canadian edged out third seed Elena Rybakina in a marathon encounter that required three tie-breaks to be resolved.
Fernandez prevailed 6-7 7-6 7-6 after three hours and 12 minutes on court, continuing a strong run that had earlier seen her knock out Jessica Pegula on the DC hard courts. The Canadian was beaten by Raducanu in the 2021 US Open final.
PA
