Hingis and Mirza, who already went into the match with the longest winning streak since Jana Novotna and Helena Sukova in 1990 - they won 44 in a row - were down and out against No.3 seeds Garcia and Mladenovic, falling behind 6-1, 5-2 to one of the craftiest, hardest-hitting pairings out there.
But the No.1-seeded Hingis and Mirza fought back like they've done so many times, reeling off five games in a row to push it to a match tie-break, where they would finally end it, 1-6, 7-5, 10-5.
"It was definitely a great test, and against a great new team," Hingis said afterwards. "They were playing together for the first time this week, and I think we're going to see a lot more of them.
"We had to take our chances. You don't see much light in a dark tunnel, but then we had one or two opportunities here and there, and with one little chance we were able to turn the match around."
"At 6-1, 5-2 the only thing we could say to each other was that it was only one break," Mirza added. "That's the only positive you can find from a situation like that. We tried to hold our serve for 5-3 to give ourselves another chance, then we had a huge game at 5-3 and the momentum went in our favor.
"We're really happy to win another tournament. We're really happy with the way we fought."
The Swiss-Indian partnership is also an incredible 11-1 together in WTA doubles finals.
And the icing on the cake? On Monday, Hingis is projected to join Mirza as co-World No.1 on the WTA Doubles Rankings. It will be Hingis' first time at No.1 since the Indian Wells fortnight in 2000.
"I think it's another chapter in my career, definitely," Hingis said. "When Sania became No.1 in Charleston that was a huge stepping stone for her, and now for me, 16 years later, who would have thought I would have another opportunity to become No.1 again? It was a dream and now it's reality.
"But I've felt we're the No.1 team for a while now. It was just a question of time."
"Ditto!" Mirza added with a laugh.