First one bang: Canadian Leylah Fernandez knocked out world number two, Belarusian Aryna Sabalenka, and finished final on Thursday in Flushing Meadows in New York.
Then the second, even bigger bang: the British Emma Raducanu became the first unseeded qualifier ever - both among men and women - to make it to a grand slam final.
"Can not believe it"
-Honestly, it has gone so fast here in New York.
But I have taken one day at a time and now, three weeks later, I am in the final.
I can not believe it, she says from the center court after defeating the Greek Maria Sakkari in two straight sets.
18-year-old Raducanu started strong and took home the first set with 6-1, in the second it was smoother and ended 6-4.
Raducanu meets Canadian Leylah Fernandez in the final.
Fernandez, who turned 19 on Monday, has gone from strength to strength in the women's singles tournament at the US Open.
On the way to the final, she has beaten both world number three Naomi Osaka and three-time grand slam winner Angelique Kerber.
In the semis, she beat world number two Aryna Sabalenka after 7-6, 4-6, 6-4.
-I do not really know how I got that last point, but I'm glad I got it and I'm happy to be in the final, she says after the match.
Historical final
The final meeting between Fernandez and Raducanu is the first time since 1999 that two teenagers settle for a grand slam title on the women's side.
Then a 17-year-old Serena Williams won over the then 18-year-old Martina Hingis in the US Open.
Raducanu seems to take the upcoming final in stride.
-I'm a qualifier so I really have no expectations at all, she says.