"Oh my God. It means the world," the 24-year-old said after reaching her first final at Flushing Meadows.
"I'm trying to process that right now. It's absolutely a dream come true. This has been a dream of mine like forever to be in the US Open final and the hope is to be the champion."
Twice New York champion Osaka was playing in her first major semi-final since 2021 and embraced the big occasion in the prime-time glare of Arthur Ashe Stadium.
The pair twice traded breaks in a tight opening set, and after a delayed line call by the automated system disrupted play Osaka refocused and let out a big roar when Anisimova hit a shot into the net on set point in the tiebreak.
The 23rd seed struggled to carry the momentum forward in the next set, however, with Anisimova matching Osaka's intensity.
After the players traded ferocious hits for 12 games in the next set, Anisimova pounced in the tiebreak to drag the match to a decider.
The eighth seed, who lost 6-0, 6-0 to Iga Swiatek in the Wimbledon final two months ago, surged ahead 4-1 thanks to a forehand winner and held her nerve from there to close out the victory and reach back-to-back Grand Slam finals.
'Mental game'
"It just shows that I've worked really hard, especially on my mental game and not giving up," Anisimova said.
"Like today, I could have easily said, 'Oh she's playing better than me, and I can't really do anything'. I really tried to find a way any way I could to stay in the match, even though it was extremely tough, and she was playing great tennis.
"I've really worked on myself to really be able to handle those moments and to believe in myself ... and especially since the Wimbledon final. I've shifted with my attitude, as well."
Japanese player Osaka said she felt inspired rather than disappointment after her display.
"I don't feel sad. It's really weird ... because I just feel like I did the best that I could," she added.
"Honestly, it's kind of inspiring for me, because it makes me just want to train and try to get better, and hopefully, just give it my very best shot again and see what happens.
"But I think I can't be mad or upset at myself."