Reigning world champion Lauren Price of Britain made a thrilling last-round comeback to reach the Olympic women's middleweight final, where she will face Li Qian, who earned herself a shot at winning China's first boxing gold since London 2012.
Price beat Nouchka Fontijn by the slimmest of margins to deprive the Dutchwoman of a place in the final for a second successive Games, while Li overcame Russian Zenfira Magomedalieva in a tough and at times scrappy bout.
In the men's lightweight semis, Cuban Andy Cruz showed his class to beat Australian Harry Garside of Australia with a unanimous decision.
Garside was unrelenting in his attack and took the fight to the double world champion, but his quickfire punches were no match for the Cuban's precision.
Cruz will take on Keyshawn Davis in the gold medal bout after the American ended Armenia's hopes of a Tokyo Olympics gold medal with his defeat of Hovhannes Bachkov.
Price came out battling from the start, but Fontijn showed her composure to keep the Briton's quick punches at bay and win the round by a narrow margin, with the prospect of a first Dutch boxing gold in nearly a century awaiting her if she qualified.
Price was docked a point for excessive holding in the second round and left herself with an uphill struggle but turned the fight around in the final round to pull off a stunning win.
"It was all in the last round," Price said. "I needed a big last round ... It doesn't get harder than that today."
She said she was no stranger to finals at major championships but the Olympics was extra special.
"It's everyone's dream, I'm going to do my utmost to win gold," she said.
Li, bronze medallist at the Rio Olympics and a two-times world middleweight champion, will face Price in Sunday's final and is one of two Chinese boxers with a shot at a Tokyo gold.
Li overcame a docked point against Magomedalieva and held her nerve to prevail in a tricky contest and celebrated long before her win was announced.