NEW YORK, NY, USA - No.8 seeds Victoria Azarenka and Ashleigh Barty came back from the brink to defeat top seeds and Roland Garros champions, Timea Babos and Kristina Mladenovic, 2-6, 7-5, 6-1, to reach the US Open semifinals.

Barty, who will return to World No.1 in the singles rankings despite bowing out in the fourth round, and Azarenka rallied from a set and 4-2 down to win 11 of the final 13 games in one hour and 48 minutes in front of an enthralled Louis Armstrong Stadium.

"Doubles is so appreciated here, especially with the fans, who get to watch it live, and it’s a lot of fun," Azarenka said. "It’s a little different to watch it on TV, but being in the stadium, you can see the players light up a little more. It’s really exciting."

Barty paired with CoCo Vandeweghe to win the US Open women's doubles title last year, saving a match point to defeat Babos and Mladenovic in a third set tie-break. Playing with Azarenka, a fellow former WTA singles World No.1 with a strong doubles resume, since the start of 2019, the two won their first title together at the Internazionali BNL d'Italia.

"We’ve played a few tournaments but it’s not like we’ve been playing every single week," Barty said after the match. "I feel like, right from the get-go, we gelled well together, we’ve enjoyed each other’s company, and we try to do our best in every tournament we play. To be in the latter stages of a slam is really exciting."

Babos and Mladenovic have been in imperious form at major tournaments since reuniting last year, reaching the quarterfinals or better of all eight Grand Slam events (winning two). Against Azarenka and Barty, the top seeds emerged from an early exchange of breaks to sweep the opening set and play strong tennis to break first in the second.

"I felt like we were close, and it was just a matter of keeping some scoreboard pressure and then taking our opportunities a little bit better. We had opportunities and perhaps some half-sniffs in the first set and just missed on the execution. So, it was more about executing and hanging in there."

It all seemed to change, however, once Azarenka held her serve to narrow the gap to 4-3; Mladenovic threw in a double fault on break point and the No.8 seeds were back in it, leveling the match and racing out to a 4-0 lead in the third.

Though Babos and Mladenovic grabbed one of the breaks back, Azarenka and Barty wrested back the momentum to serve out their spot in the semifinals, where they will next face either No.3 seeds and Wimbledon runner-ups Gabriela Dabrowski and Xu Yi-Fan or Aliaksandra Sasnovich and Viktoria Kuzmova.

For Azarenka - who fell in the first round to No.9 seed and countrywoman Aryna Sabalenka in singles - it is her best Grand Slam result in doubles since 2011, when she finished runner-up with Maria Kirilenko at the Australian Open.

"We both know from the beginning of the tournament that we’re playing both events," Azarenka said. "Singles will always be our priorities, but once that’s out, we’re very serious about doubles, and so, I don’t think there’s much adjustment. We want to play both events as well as we possibly can."

Earlier in the day, No.4 seeds Sabalenka and partner Elise Mertens kept their hopes of a first major title alive; the Sunshine Double champions knocked out No.12 seeds and French Open finalists Duan Ying-Ying and Zheng Saisai, 6-4, 6-3 to reach their second major semifinal of 2019.