The Polish-American duo beat Germany's Kevin Krawietz and Andreas Mies 4-6, 7-6, 10-5 in the quarterfinals on Friday.
Hurkacz and Isner will now take on the Netherlands' Wesley Koolhof and Britain's Neal Skupski for a place in the championship match.
Earlier on Friday, Hurkacz bowed out of the men’s singles at the Madrid Open after being overpowered by world No. 1 Novak Djokovic in the quarterfinals.
The 25-year-old Pole, ranked 14th in the world, succumbed 3-6, 4-6 to the Serbian ace in the Spanish capital.
Meanwhile, Poland's Iga Świątek, the world No. 1 in women's tennis, said last month she would miss the Madrid Open due to a shoulder injury.
The 2022 Madrid Open runs until Sunday.
(gs)
Source: PAP