Against Tatiana Bua and Daniela Seguel, who had been victorious in three match tie-breaks in their three previous matches this week, the second-seeded Barty and Dellacqua found themselves down a set and 5-1. Bua and Seguel eventually had three match points on Bua's serve at 5-2, but Barty and Dellacqua fought those off and turned the tides - forcing a match tie-break.
Barty and Dellacqua kept their momentum and secured a 4-6, 7-5, 10-4 triumph.
"We have lost many matches where we've been in their position," Dellacqua said. "We have learned that in this format, you just have to hang in there. That's what we did today. We hung around like a bad smell and eventually we got there."
"I said to Casey, 'At the end of the day, we're going to Paris this afternoon. We get to be in a beautiful city and play in a Grand Slam tournament,'" Barty said. "That kind of freed us up a little bit. From when we had match points down, we buckled down and became more pro-active and were the more dominant team out there. We won a few ugly matches this week but we did what we needed to do and got to walk away with a title, which is amazing."
Having little clay court experience together before this week, three-time Grand Slam runners-up Barty and Dellacqua now take some momentum into the French Open.
"This was our first win on clay," Barty said. "We lost in the first round of the French last year and didn't have a chance to play beforehand. Knowing we're one of the few teams going in there having won our last match will give us a lot of confidence. Hopefully the draw will be kind to us and we can work our way in there, but you never know."
Meanwhile, in Nürnberg, Karolina Pliskova shook off her loss in the singles final earlier in the day to team up with Michaella Krajicek for a 6-0, 4-6, 10-8 defeat of Raluca Olaru and Shahar Peer in the doubles final.
Krajicek and Pliskova were paired up for the first time this week. Krajicek now has five WTA doubles titles to her name, and Pliskova has two.
"I was very happy with the way we played," Krajicek said. "The first set went very smoothly. In the second set, they played a good game on my serve, where we just missed one ball. But in the tie-break, we picked up our level and I'm happy that we won."