It was pretty high stakes as the two battled it out over rolls of toilet paper and some Solo cups.
So they started flipping, and Robbie got off to a strong start.
But then Fallon started catching up!! It was truly a make or break moment for Robbie.
But because of the badass that she is, she continued to dominate. Look at that perfect line of cups!!!
And not surprisingly, she slayed Fallon.
Watch the full battle go down in the clip below: