China's Xu Xin and Liu Shiwen and Japan's Jun Mizutani and Mima Ito won their mixed doubles semi-finals on Sunday to reach the event's first Olympic final.
World number two Xu, 31, and world champion Liu, 30, beat French pair Emmanuel Lebesson and Yuan Jia Nan 4-0.
"From the start to the middle to the end, we took the game to them," Xu told reporters.
"We prepared for difficulties. We didn't think we'll win 4-0," Liu said.
"When we were down 7-10 (in the third game), Xu Xin reminded me to take it one point at a time. We have a trust. The third game was crucial," she said.
Joining them in the final will be Rio 2016 bronze medallist Mizutani, 32, and women's world number two Ito, who beat Taiwan's Lin Yun Ju and Cheng I Ching 4-1.
Mizutani and Ito were greeted by applause, air hugs and air hand embrace from their team mates as they headed to the mixed zone.
Their victory came after narrowly winning their quarter-finals against German Patrick Franziska and Petrissa Solja.
"I'm really happy that we're making table tennis history. We're carrying on the momentum to the finals," Mizutani told reporters.
"I look forward to the game because it's against China. We haven't had a chance to compete with them for a while," said Ito.
The Japanese pair are from the same hometown and have known each other since childhood.
"Mizutani has been like a big brother to me since we were young, and someone whom I respect and admire. I'm really happy to be able to compete in the mixed doubles with him," Ito, 20, told reporters after the quarter-final.
The mixed doubles makes its Olympic debut this year at the Tokyo Metropolitan Gymnasium, with 16 pairs competing for the first Olympic gold in best-of-seven matches.
In the second round of the women's singles event, South Korean teenager Shin Yubin beat Luxembourg's Ni Xia Lian, at 58 the oldest table tennis player at the Tokyo Olympics, 4-3.
Ni is competing at her fifth Olympics.
"I like to show the people I still can play table tennis... It doesn't matter how much you win, how much you lose, you cannot lose as a person. You have to fight, fight," Ni told Reuters.
"If you lose, you can forgive your ability is not enough. The opponent is stronger? Congratulations, I will try next time. But we have to be a player to fight," she said.
(Reporting by Eimi Yamamitsu; Editing by Muralikumar Anantharaman and Ed Osmond)
