Dabrowski and Routliffe, who began their partnership just last month, saved eight of the nine break points they faced during a match that lasted two hours, 14 minutes.
It marked the first Grand Slam title for Routliffe, who previously represented Canada, and third for Dabrowski following the mixed doubles titles she won at the 2017 French Open and 2018 Australian Open.
"Thanks to Gabby for playing with me. She really took a chance on me and I really appreciate it and love her for it," Routliffe said during their on-court interview. "And obviously I hope we can have many great results to come in the future."
Siegemund and Zvonareva, who won the 2020 US Open women's doubles competition, failed to convert any of the five break point opportunities they had in a tightly-contested first set that required a drama-filled tiebreaker.
A quick start to the tiebreaker gave Dabrowski and Routliffe a 4-0 lead but Siegemund and Zvonareva stormed back to make it 4-4 and even earned a pair of set points but it was the Canadian and New Zealander who clinched it on their fourth set point.
Dabrowski and Routliffe took that momentum into the second set where they quickly went up a double break for a 3-0 lead that set them on their way as they went on to break again when they closed out the match on their third championship point.
"Thank you to Erin. You took a chance on me too," said Dabrowski. "I'm really, really proud of the way that we've stood by each other through thick and thin the last two weeks.
"I think we improved a lot even from the first tournament we played back in Montreal."
