NEW YORK -- Anna Danilina and Harri Heliovaara defeated top seeds Jessica Pegula and Austin Krajicek 6-3, 6-4 to win the US Open mixed doubles title.

Ranked No.29 in doubles on the Hologic WTA Tour, the title is Danilina's first Grand Slam title and delivered Kazakhstan its first Grand Slam mixed doubles title. It is the 28-year-old's fifth doubles title overall, having already won four on the WTA Tour. Earlier this year, she captured the Hamburg title with Alexandra Panova.

Playing together for the first time, Danilina and Heliovaara lost just one set during their title run. That came in their first match together, a 6-3, 5-7, [10-7] win over Nicole Melichar-Martinez and Matthew Ebden. 

From there, the Kazakh-Finnish duo rolled to the title. They defeated Alycia Parks and Denis Kudla, Xu YiFan and Jorgen Vliegen, and Ena Shibahara and Mate Pavic before toppling the top seeds in 72 minutes on Saturday. It was a remarkable run for a team who had never met or spoken before signing in together at the registration desk. 

"I have no words," Danilina said. "It was an amazing run. It's been a pleasure. To many more."

Danilina and Heliovaara held serve all but once against Pegula and Krajicek, who were playing in their first mixed doubles final after seven appearances together. The American team came through to their first final by navigating a difficult draw. They defeated Laura Siegemund and Sander Gille, Bethanie Mattek-Sands and Jamie Murray, Ellen Perez and Jean-Julian Rojer, and Taylor Towsend and Ben Shelton. All but one of their victories came in the deciding match tiebreak. 

Along with Coco Gauff, Pegula will rise to WTA Doubles No.1 on Monday. It will be her first stint in the top spot of either singles or doubles.