The final will pit power against power when Andreescu takes on her childhood hero Williams, who claimed her first US Open title in 1999 before Andreescu was even born.
Canadian teenager Bianca Andreescu's dream run at the US Open continued on Thursday as she powered past Belinda Bencic 7-6(3), 7-5 to set up a highly-anticipated final with Serena Williams on Saturday.
Andreescu, who has already won titles at Indian Wells and Toronto during her breakout 2019 season, unleashed a torrent of bruising groundstrokes after falling behind 2-5 in the second set, winning five straight games to punch her ticket to her first Grand Slam final.
"It is just surreal," the 19-year-old said in an on-court interview at Arthur Ashe Stadium.
"I don't know what to say. It is a dream come true to play Serena in the finals of the US Open. It's crazy."
After a strong start from the Swiss, momentum shifted on the first point of the first set tiebreak when Bencic double faulted and her previously immaculate play began to crumble.
Andreescu quickly ran out to a 5-0 lead in the breaker that she won comfortably to capture the first set.
Bencic finally broke Andreescu to open the second set but despite stretching her lead to 5-2, Andreescu fed off the supportive crowd to level at 5-5 after another costly Bencic double fault.
A flustered Bencic struggled from there, giving a sarcastic thumbs up to the crowd when they applauded the double fault before sending a forehand into the net on match point to end the first-time encounter between two of the game's rising stars.
The final will pit power against power when Andreescu takes on her childhood hero Williams, who claimed her first US Open title in 1999 before Andreescu was even born.
Despite being sidelined at times with injury this year, Andreescu has been a giant slayer when healthy, posting a 7-0 record against top 10 opponents and a 33-4 record overall.
Her route to the final has included wins over former world number one Caroline Wozniacki and rising Belgian Elise Mertens.
Thursday's win marks a remarkable turnaround for the Ontario native who was born to Romanian parents in 2000.
Andreescu lost in the first round of US Open qualifiers last year and finished 2018 ranked world number 178 but will be at least world number nine on Monday and world number five if she can upset Williams.
In their only previous meeting Andreescu led Williams 3-1 at the Rogers Cup final in Toronto last month before the 37-year-old was forced to retire due to back spasms.
The Canadian was widely praised for comforting the tearful Williams after the match.
Andreescu will have her work cut out for her when she takes on an in-form Williams, who crushed Elina Svitolina 6-3 6-1 earlier in the evening to put her on the brink of a record-tying 24th Grand Slam title.
